Error executing VGA ROM with coreboot

[Mansoor]

Hi

I keep getting "ILLEGAL EXTENDED X86 OPCODE!" from my VGA ROM while trying
run VGA ROM in coreboot.

I tried x86emu, yabel and real mode for running VGA ROM with no luck. But
the same VGA ROM is running with seabios.

I am attaching the boot logs with x86emu, real mode and with seabios.

Any help?

What is the big difference while executing VGA ROM in coreboot and seabios?

Why coreboot can't run a VGA ROM which seabios can?

Thanks

Mansoor

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[Joe]

On 10/29/2009 07:38 AM, Mansoor wrote:
> Hi
>
> I keep getting “ILLEGAL EXTENDED X86 OPCODE!” from my VGA ROM while
> trying run VGA ROM in coreboot.
>
> I tried x86emu, yabel and real mode for running VGA ROM with no luck.
> But the same VGA ROM is running with seabios.
>
> I am attaching the boot logs with x86emu, real mode and with seabios.
>
> Any help?
>
> What is the big difference while executing VGA ROM in coreboot and seabios?
>
> Why coreboot can’t run a VGA ROM which seabios can?

Hmm looks like your getting Unexpected Exception errors. Something is 
not initializing correctly. Memory maybe?

[Mansoor]

> -----Original Message-----
> From: Joe [mailto:[e-mail]]
> Sent: Thursday, October 29, 2009 7:32 PM
> To: Mansoor
> Cc: 'coreboot'
> Subject: Re: [coreboot] Error executing VGA ROM with coreboot
>
> On 10/29/2009 07:38 AM, Mansoor wrote:
> > Hi
> >
> > I keep getting "ILLEGAL EXTENDED X86 OPCODE!" from my VGA ROM while
> > trying run VGA ROM in coreboot.
> >
> > I tried x86emu, yabel and real mode for running VGA ROM with no luck.
> > But the same VGA ROM is running with seabios.
> >
> > I am attaching the boot logs with x86emu, real mode and with seabios.
> >
> > Any help?
> >
> > What is the big difference while executing VGA ROM in coreboot and
>
> seabios?
> > Why coreboot can't run a VGA ROM which seabios can?
>
> Hmm looks like your getting Unexpected Exception errors. Something is
> not initializing correctly. Memory maybe?

I don't think so, because with seabios I am able to load Linux in GUI mode.
Only with coreboot I am facing these issues for initializing VGA ROM.
> DISCLAIMER: This e-mail and any attachment (s) is for authorised use by
> the
> intended recipient (s) only. It may contain proprietary material,
> confidential
> information and/or be subject to the legal privilege of iWave Systems
> Technologies Private Limited. If you have received this message in error,
> please notify the originator immediately. If you are not the intended
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> you
> for your co-operation.

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[Joseph Smith]

On Fri, 30 Oct 2009 10:11:36 +0530, "Mansoor" 
wrote:
> > -----Original Message-----
> > From: Joe [mailto:[e-mail]]
> > Sent: Thursday, October 29, 2009 7:32 PM
> > To: Mansoor
> > Cc: 'coreboot'
> > Subject: Re: [coreboot] Error executing VGA ROM with coreboot
> >
> > On 10/29/2009 07:38 AM, Mansoor wrote:
> > > Hi
> > >
> > > I keep getting "ILLEGAL EXTENDED X86 OPCODE!" from my VGA ROM while
> > > trying run VGA ROM in coreboot.
> > >
> > > I tried x86emu, yabel and real mode for running VGA ROM with no luck.
> > > But the same VGA ROM is running with seabios.
> > >
> > > I am attaching the boot logs with x86emu, real mode and with seabios.
> > >
> > > Any help?
> > >
> > > What is the big difference while executing VGA ROM in coreboot and
> >
> > seabios?
> > > Why coreboot can't run a VGA ROM which seabios can?
> >
> > Hmm looks like your getting Unexpected Exception errors. Something is
> > not initializing correctly. Memory maybe?
>
> I don't think so, because with seabios I am able to load Linux in GUI

mode.
> Only with coreboot I am facing these issues for initializing VGA ROM.

You could always try Debugging the Unexpected Exception errors with GDB,
this may give you a clue on what the problem is.

http://www.coreboot.org/Debugging

> On Fri, 30 Oct 2009 10:11:36 +0530, "Mansoor" 
> wrote:
> > > -----Original Message-----
> > > From: Joe [mailto:[e-mail]]
> > > Sent: Thursday, October 29, 2009 7:32 PM
> > > To: Mansoor
> > > Cc: 'coreboot'
> > > Subject: Re: [coreboot] Error executing VGA ROM with coreboot
> > >
> > > On 10/29/2009 07:38 AM, Mansoor wrote:
> > > > Hi
> > > >
> > > > I keep getting "ILLEGAL EXTENDED X86 OPCODE!" from my VGA ROM while
> > > > trying run VGA ROM in coreboot.
> > > >
> > > > I tried x86emu, yabel and real mode for running VGA ROM with no luck.
> > > > But the same VGA ROM is running with seabios.
> > > >
> > > > I am attaching the boot logs with x86emu, real mode and with seabios.
> > > >
> > > > Any help?
> > > >
> > > > What is the big difference while executing VGA ROM in coreboot and
> > >
> > > seabios?
> > > > Why coreboot can't run a VGA ROM which seabios can?
> > >
> > > Hmm looks like your getting Unexpected Exception errors. Something is
> > > not initializing correctly. Memory maybe?
> >
> > I don't think so, because with seabios I am able to load Linux in GUI
>
> mode.
> > Only with coreboot I am facing these issues for initializing VGA ROM.
>
> You could always try Debugging the Unexpected Exception errors with GDB,
> this may give you a clue on what the problem is.
>
> http://www.coreboot.org/Debugging

Actually i tried GDB and failed to build the image.. I got  section
overlap error and was not able to solve it.

What i didnt understand is

Why coreboot can't run a VGA ROM which seabios can?
What is the big difference while executing VGA ROM in coreboot and
seabios?
> From the log you can see seabios emits some warning messages(fail

handle_155fXX) but still it continues to run the VGA ROM, where x86emu or
realmode hangs with error messages

in seabios
fail handle_155fXX:23(86):

a=a0005f38  b=000008c1  c=00000003  d=0000c000 ds=a000 es=c000 ss=a000

si=00000000 di=00000003 bp=000077cc sp=000077be cs=c000 ip=3115  f=0002

Real mode

Real mode stub @00000500: 422 bytes

Calling Option ROM...

oprom: INT# 0x8e41a854

oprom: eax: 8a000885 ebx: 0e21e039 ecx: 00028101 edx: 2989b606

oprom: ebp: 58000a58 esp: c0010004 edi: c668404c esi: c2650304

oprom:  ip: e6b0      cs: 8831   flags: 00002900

Unexpected Exception: 6 @ 10:f6fdd07d - Halting

Code: 0 eflags: 00010012

eax: 00007776 ebx: 00008831 ecx: 0010ef73 edx: 001059b1

edi: c0010004 esi: 8e41a854 ebp: 00002900 esp: 0000774a
> DISCLAIMER: This e-mail and any attachment (s) is for authorised use by
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> you
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information and/or be subject to the legal privilege of iWave Systems
Technologies Private Limited. If you have received this message in error,
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[Joseph Smith]

On Fri, 30 Oct 2009 17:32:03 +0530 (IST), [e-mail] wrote:
> > On Fri, 30 Oct 2009 10:11:36 +0530, "Mansoor" 
> > wrote:
> > > > -----Original Message-----
> > > > From: Joe [mailto:[e-mail]]
> > > > Sent: Thursday, October 29, 2009 7:32 PM
> > > > To: Mansoor
> > > > Cc: 'coreboot'
> > > > Subject: Re: [coreboot] Error executing VGA ROM with coreboot
> > > >
> > > > On 10/29/2009 07:38 AM, Mansoor wrote:
> > > > > Hi
> > > > >
> > > > > I keep getting "ILLEGAL EXTENDED X86 OPCODE!" from my VGA ROM while
> > > > > trying run VGA ROM in coreboot.
> > > > >
> > > > > I tried x86emu, yabel and real mode for running VGA ROM with no

luck.
> > > > > But the same VGA ROM is running with seabios.
> > > > >
> > > > > I am attaching the boot logs with x86emu, real mode and with

seabios.
> > > > > Any help?
> > > > >
> > > > > What is the big difference while executing VGA ROM in coreboot and
> > > >
> > > > seabios?
> > > > > Why coreboot can't run a VGA ROM which seabios can?
> > > >
> > > > Hmm looks like your getting Unexpected Exception errors. Something is
> > > > not initializing correctly. Memory maybe?
> > >
> > > I don't think so, because with seabios I am able to load Linux in GUI
> >
> > mode.
> > > Only with coreboot I am facing these issues for initializing VGA ROM.
> >
> > You could always try Debugging the Unexpected Exception errors with GDB,
> > this may give you a clue on what the problem is.
> >
> > http://www.coreboot.org/Debugging
>
> Actually i tried GDB and failed to build the image.. I got  section
> overlap error and was not able to solve it.
>
> What i didnt understand is
>
> Why coreboot can't run a VGA ROM which seabios can?
> What is the big difference while executing VGA ROM in coreboot and
> seabios?
>
> From the log you can see seabios emits some warning messages(fail
> handle_155fXX) but still it continues to run the VGA ROM, where x86emu or
> realmode hangs with error messages
>
> in seabios
> fail handle_155fXX:23(86):
>
> a=a0005f38  b=000008c1  c=00000003  d=0000c000 ds=a000 es=c000 ss=a000
>
> si=00000000 di=00000003 bp=000077cc sp=000077be cs=c000 ip=3115  f=0002
>
> Real mode
>
> Real mode stub @00000500: 422 bytes
>
> Calling Option ROM...
>
> oprom: INT# 0x8e41a854
>
> oprom: eax: 8a000885 ebx: 0e21e039 ecx: 00028101 edx: 2989b606
>
> oprom: ebp: 58000a58 esp: c0010004 edi: c668404c esi: c2650304
>
> oprom:  ip: e6b0      cs: 8831   flags: 00002900
>
> Unexpected Exception: 6 @ 10:f6fdd07d - Halting
>
> Code: 0 eflags: 00010012
>
> eax: 00007776 ebx: 00008831 ecx: 0010ef73 edx: 001059b1
>
> edi: c0010004 esi: 8e41a854 ebp: 00002900 esp: 0000774a

well lets see,
The coreboot rom emulators are completely different beasts than seabios.
Perhaps you take a look at the differences in the interrupt handlers to
find out the differences?

I would suggest running YABEL in full DEBUG mode, YABEL is able to output
rom PCI accesses, io accesses, interrupt calls etc. I would also suggest if
you do this to output your bootlog to a text file in minicom, because it
may run for several hours and get quite large. I would be glad to take a
look at it and see if I can see what is going on.

[Mansoor]

Hi All

I have attached the YABEL output.

Even though coreboot does only the hardware initialization, it has to do a
VGA rom init for payloads other than seabios? 
I my case I was planning to use FILO as payload to boot Linux. FILO doesn't
do any VGA init.
> -----Original Message-----
> From: Joseph Smith [mailto:[e-mail]]
> Sent: Friday, October 30, 2009 6:22 PM
> To: [e-mail]
> Cc: coreboot
> Subject: Re: [coreboot] Error executing VGA ROM with coreboot
> Importance: Low
>
> On Fri, 30 Oct 2009 17:32:03 +0530 (IST), [e-mail] wrote:
> > > On Fri, 30 Oct 2009 10:11:36 +0530, "Mansoor"
>
> > > wrote:
> > > > > -----Original Message-----
> > > > > From: Joe [mailto:[e-mail]]
> > > > > Sent: Thursday, October 29, 2009 7:32 PM
> > > > > To: Mansoor
> > > > > Cc: 'coreboot'
> > > > > Subject: Re: [coreboot] Error executing VGA ROM with coreboot
> > > > >
> > > > > On 10/29/2009 07:38 AM, Mansoor wrote:
> > > > > > Hi
> > > > > >
> > > > > > I keep getting "ILLEGAL EXTENDED X86 OPCODE!" from my VGA ROM while
> > > > > > trying run VGA ROM in coreboot.
> > > > > >
> > > > > > I tried x86emu, yabel and real mode for running VGA ROM with no
>
> luck.
> > > > > > But the same VGA ROM is running with seabios.
> > > > > >
> > > > > > I am attaching the boot logs with x86emu, real mode and with
>
> seabios.
> > > > > > Any help?
> > > > > >
> > > > > > What is the big difference while executing VGA ROM in coreboot and
> > > > >
> > > > > seabios?
> > > > > > Why coreboot can't run a VGA ROM which seabios can?
> > > > >
> > > > > Hmm looks like your getting Unexpected Exception errors. Something is
> > > > > not initializing correctly. Memory maybe?
> > > >
> > > > I don't think so, because with seabios I am able to load Linux in GUI
> > >
> > > mode.
> > > > Only with coreboot I am facing these issues for initializing VGA ROM.
> > >
> > > You could always try Debugging the Unexpected Exception errors with

GDB,
> > > this may give you a clue on what the problem is.
> > >
> > > http://www.coreboot.org/Debugging
> >
> > Actually i tried GDB and failed to build the image.. I got  section
> > overlap error and was not able to solve it.
> >
> > What i didnt understand is
> >
> > Why coreboot can't run a VGA ROM which seabios can?
> > What is the big difference while executing VGA ROM in coreboot and
> > seabios?
> >
> > From the log you can see seabios emits some warning messages(fail
> > handle_155fXX) but still it continues to run the VGA ROM, where x86emu
>
> or
> > realmode hangs with error messages
> >
> > in seabios
> > fail handle_155fXX:23(86):
> >
> > a=a0005f38  b=000008c1  c=00000003  d=0000c000 ds=a000 es=c000
>
> ss=a000
> > si=00000000 di=00000003 bp=000077cc sp=000077be cs=c000 ip=3115
>
> f=0002
> > Real mode
> >
> > Real mode stub @00000500: 422 bytes
> >
> > Calling Option ROM...
> >
> > oprom: INT# 0x8e41a854
> >
> > oprom: eax: 8a000885 ebx: 0e21e039 ecx: 00028101 edx: 2989b606
> >
> > oprom: ebp: 58000a58 esp: c0010004 edi: c668404c esi: c2650304
> >
> > oprom:  ip: e6b0      cs: 8831   flags: 00002900
> >
> > Unexpected Exception: 6 @ 10:f6fdd07d - Halting
> >
> > Code: 0 eflags: 00010012
> >
> > eax: 00007776 ebx: 00008831 ecx: 0010ef73 edx: 001059b1
> >
> > edi: c0010004 esi: 8e41a854 ebp: 00002900 esp: 0000774a
>
> well lets see,
> The coreboot rom emulators are completely different beasts than seabios.
> Perhaps you take a look at the differences in the interrupt handlers to
> find out the differences?
>
> I would suggest running YABEL in full DEBUG mode, YABEL is able to output
> rom PCI accesses, io accesses, interrupt calls etc. I would also suggest
> if
> you do this to output your bootlog to a text file in minicom, because it
> may run for several hours and get quite large. I would be glad to take a
> look at it and see if I can see what is going on.
>
> DISCLAIMER: This e-mail and any attachment (s) is for authorised use by
> the
> intended recipient (s) only. It may contain proprietary material,
> confidential
> information and/or be subject to the legal privilege of iWave Systems
> Technologies Private Limited. If you have received this message in error,
> please notify the originator immediately. If you are not the intended
> recipient, you are notified that you are strictly prohibited from
> retaining,
> using, copying, alerting or disclosing the content of this message. Thank
> you
> for your co-operation.

------------------------------------------------------------------------------- 
DISCLAIMER: This e-mail and any attachment (s) is for authorised use by the
intended recipient (s) only. It may contain proprietary material, confidential
information and/or be subject to the legal privilege of iWave Systems
Technologies Private Limited. If you have received this message in error,
please notify the originator immediately. If you are not the intended
recipient, you are notified that you are strictly prohibited from retaining,
using, copying, alerting or disclosing the content of this message. Thank you
for your co-operation. 
------------------------------------------------------------------------------

[Kevin O'Connor]

On Sat, Oct 31, 2009 at 01:14:21PM +0530, Mansoor wrote:
[...]
> c000:0087 0f01                 ILLEGAL EXTENDED X86 OPCODE
> c000:0087: 01 ILLEGAL EXTENDED X86 OPCODE!
> halt_sys: file /prdmd/coreboot-v2/src/devices/../../util/x86emu/x86emu/ops2.c, line 60
> halted
>    AX=0000  BX=0000  CX=0000  DX=0080  SP=ffec  BP=0000  SI=0000  DI=0057
>    DS=c000  ES=0000  SS=1000  CS=c000  IP=0089   NV UP EI PL NZ NA PO NC
> c000:0089 e0                   ILLEGAL EXTENDED X86 OPCODE

If I dissasemble 0f01e0 I get:

0:   0f 01 e0                smsww  %ax

Though, that might differ depending on the next bytes?

In any case, I get the feeling your rom may be about to enter 32bit
mode..

You might want to try running:

objdump -m i386 -M i8086 -M suffix -D -b binary myvgarom.rom

and see what it says is at offset 0x0087.

-Kevin

[Joseph Smith]

On 10/31/2009 10:29 AM, Kevin O'Connor wrote:
> On Sat, Oct 31, 2009 at 01:14:21PM +0530, Mansoor wrote:
> [...]
> > c000:0087 0f01                 ILLEGAL EXTENDED X86 OPCODE
> > c000:0087: 01 ILLEGAL EXTENDED X86 OPCODE!
> > halt_sys: file /prdmd/coreboot-v2/src/devices/../../util/x86emu/x86emu/ops2.c, line 60
> > halted
> >    AX=0000  BX=0000  CX=0000  DX=0080  SP=ffec  BP=0000  SI=0000  DI=0057
> >    DS=c000  ES=0000  SS=1000  CS=c000  IP=0089   NV UP EI PL NZ NA PO NC
> > c000:0089 e0                   ILLEGAL EXTENDED X86 OPCODE
>
> If I dissasemble 0f01e0 I get:
> 0:   0f 01 e0                smsww  %ax
>
> Though, that might differ depending on the next bytes?
>
> In any case, I get the feeling your rom may be about to enter 32bit
> mode..
>
> You might want to try running:
>
> objdump -m i386 -M i8086 -M suffix -D -b binary myvgarom.rom
>
> and see what it says is at offset 0x0087.

Interesting, the Atom has a 32-bit vga bios?
Mansoor please let us know what 0x0087 says.

[Peter Stuge]

Mansoor wrote:
> I have attached the YABEL output.

Thanks. I think it is helpful. Please follow Kevin's suggestions to
find out more about what the ROM is trying to do.
> Even though coreboot does only the hardware initialization, it has
> to do a VGA rom init for payloads other than seabios?

VGA is often not very important for payloads, and option ROMs in
general fundamentally require a BIOS, which coreboot does not, and
shall not, offer. If a BIOS environment is needed, then SeaBIOS is
the way to go.
> I my case I was planning to use FILO as payload to boot Linux. FILO
> doesn't do any VGA init.

In theory it can, if libpayload has native support for your graphics
hardware. Since this isn't the case, there is no init done. There
exists only very few graphics drivers in libpayload, which would
support the idea that graphics is not very important for payloads.

I think there are a few options that you can explore further. First,
maybe the graphics driver in Linux has the ability to initialize
hardware completely? Because Linux will be started pretty quickly
with coreboot+FILO, the delay from power on until graphics enabled
will not be very long even if it is postponed to Linux.

Second, you can use both SeaBIOS and FILO together. SeaBIOS supports
booting using another payload file than itself in CBFS. Normally this
is used as a last resort when there is no local storage or option ROM
to boot from, but that behavior should be very easy to change in
SeaBIOS, so that FILO is always used for booting.

Using multiple payloads will increase boot time, but if legacy VGA
ROM initialization is a hard requirement then I'm afraid there is no
substitute for a BIOS environment, such as provided by SeaBIOS.

But, don't rule out the Linux graphics driver alternative. There
exists at least one driver (for AMD Geode) which does this, one or
several of the VIA hardware drivers may also be able to do it. Linux
2.6.31 got kernel modesetting support in the Intel framebuffer driver
so there is a chance. Also, the Intel graphics drivers developers are
very active in the Linux community, and maybe they can quickly add
any features that are discovered to be missing at the moment.

//Peter

[Mansoor]

> -----Original Message-----
> From: coreboot-bounces+mansoor=[e-mail]
> [mailto:coreboot-bounces+mansoor=[e-mail]] On Behalf
> Of Peter Stuge
> Sent: Sunday, November 01, 2009 4:14 AM
> To: [e-mail]
> Subject: Re: [coreboot] Error executing VGA ROM with coreboot
>
> Mansoor wrote:
> > I have attached the YABEL output.
>
> Thanks. I think it is helpful. Please follow Kevin's suggestions to
> find out more about what the ROM is trying to do.

Yes. I will do it
> > Even though coreboot does only the hardware initialization, it has
> > to do a VGA rom init for payloads other than seabios?
>
> VGA is often not very important for payloads, and option ROMs in
> general fundamentally require a BIOS, which coreboot does not, and
> shall not, offer. If a BIOS environment is needed, then SeaBIOS is
> the way to go.
> > I my case I was planning to use FILO as payload to boot Linux. FILO
> > doesn't do any VGA init.
>
> In theory it can, if libpayload has native support for your graphics
> hardware. Since this isn't the case, there is no init done. There
> exists only very few graphics drivers in libpayload, which would
> support the idea that graphics is not very important for payloads.

I don't think libpayload has support for my hardware
> I think there are a few options that you can explore further. First,
> maybe the graphics driver in Linux has the ability to initialize
> hardware completely? Because Linux will be started pretty quickly
> with coreboot+FILO, the delay from power on until graphics enabled
> will not be very long even if it is postponed to Linux.

I tried this option. But it didn't initialize VGA
> Second, you can use both SeaBIOS and FILO together. SeaBIOS supports
> booting using another payload file than itself in CBFS. Normally this
> is used as a last resort when there is no local storage or option ROM
> to boot from, but that behavior should be very easy to change in
> SeaBIOS, so that FILO is always used for booting.
>
> Using multiple payloads will increase boot time, but if legacy VGA
> ROM initialization is a hard requirement then I'm afraid there is no
> substitute for a BIOS environment, such as provided by SeaBIOS.

Thanks for the detailed explanation. 
I am using this method as an alternative (coreboot loads SeaBIOS then
SeaBIOS loads FILO, FILO loads Linux) now. And it works fine. I am using
FILO because I need USB mass storage support. Extra boot time is the seaBIOS
hardware initialization time... and I say it is negligible compared to the
20-30 sec delay of factory BIOS.
> But, don't rule out the Linux graphics driver alternative. There
> exists at least one driver (for AMD Geode) which does this, one or
> several of the VIA hardware drivers may also be able to do it. Linux
> 2.6.31 got kernel modesetting support in the Intel framebuffer driver
> so there is a chance. Also, the Intel graphics drivers developers are
> very active in the Linux community, and maybe they can quickly add
> any features that are discovered to be missing at the moment.
>
> //Peter
>
> DISCLAIMER: This e-mail and any attachment (s) is for authorised use by
> the
> intended recipient (s) only. It may contain proprietary material,
> confidential
> information and/or be subject to the legal privilege of iWave Systems
> Technologies Private Limited. If you have received this message in error,
> please notify the originator immediately. If you are not the intended
> recipient, you are notified that you are strictly prohibited from
> retaining,
> using, copying, alerting or disclosing the content of this message. Thank
> you
> for your co-operation.

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[Peter Stuge]

Mansoor wrote:
> > maybe the graphics driver in Linux has the ability to initialize
> > hardware completely?
>
> I tried this option. But it didn't initialize VGA

Ok. If you prefer this solution you could, as I mentioned, try to
contact the Linux graphics driver developers. There are people from
Intel working actively there. Search keyword is drm-intel
> > Second, you can use both SeaBIOS and FILO together.
>
> Thanks for the detailed explanation. 
> I am using this method as an alternative (coreboot loads SeaBIOS
> then SeaBIOS loads FILO, FILO loads Linux) now. And it works fine.

Nice!
> Extra boot time is the seaBIOS hardware initialization time... and
> I say it is negligible compared to the 20-30 sec delay of factory
> BIOS.

He-he. :)

//Peter

[Peter Stuge]

[e-mail] wrote:
> Why coreboot can't run a VGA ROM which seabios can?
> What is the big difference while executing VGA ROM in coreboot and
> seabios?

Joe already mentioned it, but there is a big different in the amount
and quality of legacy BIOS interrupt services available at VGA ROM
run time depending on if it is run by coreboot, or by SeaBIOS.

coreboot doesn't want to have any BIOS services, while SeaBIOS
strives to be a fully featured BIOS.
> Real mode stub @00000500: 422 bytes
> Calling Option ROM...
> oprom: INT# 0x8e41a854
> oprom: eax: 8a000885 ebx: 0e21e039 ecx: 00028101 edx: 2989b606
> oprom: ebp: 58000a58 esp: c0010004 edi: c668404c esi: c2650304
> oprom:  ip: e6b0      cs: 8831   flags: 00002900
> Unexpected Exception: 6 @ 10:f6fdd07d - Halting
> Code: 0 eflags: 00010012
> eax: 00007776 ebx: 00008831 ecx: 0010ef73 edx: 001059b1
> edi: c0010004 esi: 8e41a854 ebp: 00002900 esp: 0000774a

8831:eb60 doesn't look like a place where the VGA ROM should be
executing.

Joe's suggestion to trace what is actually going on in the VGA ROM is
really good. You can use YABEL, or you can use SerialICE together
with QEMU. YABEL might be faster than SerialICE though.

//Peter

[ron minnich]

well how about this as a first step. We're getting exception 6. What
is that again?
Also: is 0x8e41a854 even remotely valid as a bios int?
And: 8831:eb60 -- 96E70 -- is that a sensible place for the CPU to be?

It looks to me like the stack is somewhere odd: 774a. Is that right?
Where does the stack start out?
Finally ... as pointed out, if the VGA bios uses services that
coreboot does not supply, it's not going to work. Some of these VGA
bioses are very badly written, and this problem can occur.

Just a few questions.

ron

[Stefan Reinauer]

ron minnich wrote:
> well how about this as a first step. We're getting exception 6. What
> is that again?
> Also: is 0x8e41a854 even remotely valid as a bios int?
> And: 8831:eb60 -- 96E70 -- is that a sensible place for the CPU to be?
>
> It looks to me like the stack is somewhere odd: 774a. Is that right?
> Where does the stack start out?
> Finally ... as pointed out, if the VGA bios uses services that
> coreboot does not supply, it's not going to work. Some of these VGA
> bioses are very badly written, and this problem can occur.

All those values look pretty far off.. Mansoor, you could enable
instruction level logging in YABEL and see where it stops looking sane..

Stefan

[ron minnich]

BTW this sort of thing can happen when the code calls a function, the
stack is bad, and it returns to la-la land. That's why I'm curious
about %esp.

ron

[Kevin O'Connor]

On Fri, Oct 30, 2009 at 05:32:03PM +0530, [e-mail] wrote:
> From the log you can see seabios emits some warning messages(fail
> handle_155fXX) but still it continues to run the VGA ROM, where x86emu or
> realmode hangs with error messages
>
> in seabios
> fail handle_155fXX:23(86):
>    a=a0005f38  b=000008c1  c=00000003  d=0000c000 ds=a000 es=c000 ss=a000
>   si=00000000 di=00000003 bp=000077cc sp=000077be cs=c000 ip=3115  f=0002

The "fail" messages from seabios just indicate that seabios is
returning an error code to the caller.  It's not indicating any kind
of failure within seabios.  This particular messages means the vga rom
tried to call "int 0x15 ax=5f38" and seabios didn't know anything
about it.  (It looks like some internal vga/bios callback thing.)

[...]
> Why coreboot can't run a VGA ROM which seabios can?
> What is the big difference while executing VGA ROM in coreboot and
> seabios?

Sorry, but I don't know either.  It's possible the vga rom is relying
on some obscure bios functionality (like fixed code locations) that
the emulators don't handle.

-Kevin