SeaBIOS March 2012

seabios@seabios.org

31 participants
85 discussions

Booting from USB thumbdrives, older drives boot, newer drives don't.
by Dave Frodin 05 Mar '12

05 Mar '12

I'm a new subscriber to seabios.org so feel free to straighten me out if needed. I've been debugging an problem we've been seeing with not being able to boot (Ubuntu specifically) off of a variety of "newer" USB thumb drives. I've been specifically looking at an older/newer pair of Sandisk Cruzer 4GB drives. I've been adding dprintf's to narrow down the problem to the blockcmd.c file. The function scsi_init_drive() queries the USB device to determine stuff like vendor/device/size/etc. Near the end of the function is a call to cdb_mode_sense_geom(&dop, &geomdata) to retrieve the info related to cyl/head type stuff. On the older/working thumbdrive it returns zeroes for all of the values that get used by the code. The newer/failing drive generates a "stall" on the USB bus, which it never recovers from. The cdb_mode_sense_geom() function is sending a SCSI CDB Mode Sense (CMD=0x5A) to the device. As a hack of a test, I removed the call to cdb_mode_sense_geom() and filled the buffer it should have returned with zeroes and the failing thumbdrive now boots. I have some searching I need to do to find out... 1) Is there a SCSI command to determine what protocols are supported? 2) Is there another SCSI command that might return similar required data? Has anyone out there experienced similar booting difficulties? Or does anyone have any recommendations on what approach I should take? thanks, Dave

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Re: [SeaBIOS] [PATCH] x86emu: Correctly handle 0x66 prefix for some instructions
by Julian Pidancet 05 Mar '12

05 Mar '12

Sorry for the noise. None of these emails got through to the xorg-devel mailing list. Will retry later. -- Julian

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[PATCH] vgabios: Fetch _rom_header_size from the global segment when computing the ROM's checksum
by Julian Pidancet 05 Mar '12

05 Mar '12

Otherwise, checksum_far is getting called with zero as the length parameter, and the ROM checksum in the header end up beeing zero after vga_post() is called. Signed-off-by: Julian Pidancet <julian.pidancet(a)gmail.com> --- vgasrc/vgabios.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/vgasrc/vgabios.c b/vgasrc/vgabios.c index 58e467d..c1b10c1 100644 --- a/vgasrc/vgabios.c +++ b/vgasrc/vgabios.c @@ -1255,6 +1255,7 @@ vga_post(struct bregs *regs) // Fixup checksum extern u8 _rom_header_size, _rom_header_checksum; SET_VGA(_rom_header_checksum, 0); - u8 sum = -checksum_far(get_global_seg(), 0, _rom_header_size * 512); + u8 sum = -checksum_far(get_global_seg(), 0, + GET_GLOBAL(_rom_header_size) * 512); SET_VGA(_rom_header_checksum, sum); } -- Julian Pidancet

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Re: [SeaBIOS] First access to the block drive
by Kevin O'Connor 05 Mar '12

05 Mar '12

On Thu, Mar 01, 2012 at 05:39:25PM +0900, Daniel Castro wrote: > Hello all, > > The xen pv drivers are almost done. > > When I start the booting process from hda seabios tries to read lba at > 0 (sector 0) buffer (buf_fl) to 7c00 count 0 operation 0 (read) > command 1 (unlisted) > I do not understand count 0 and command 1. > Should it be count 1, for the first sector on the drive and a command > such as listed in drive.h? > > Is this normal? Am I missing something? I don't understand what you are reporting/asking. The code at boot.c:boot_disk() issues a legacy bios read (int 13 ah=2) of the first sector (count=1). -Kevin

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Re: [SeaBIOS] invalid handle_legacy_disk
by Kevin O'Connor 04 Mar '12

04 Mar '12

On Sun, Mar 04, 2012 at 10:13:56PM +0100, Christian Gmeiner wrote: > Am 4. März 2012 19:54 schrieb Kevin O'Connor <kevin(a)koconnor.net>: > > On Fri, Mar 02, 2012 at 09:32:38AM +0100, Christian Gmeiner wrote: > >> What is the cause of this error message? > > > > It means an application (eg, a bootloader) called a BIOS function with > > an invalid parameter. It's not a SeaBIOS error condition. (Indeed, > > it's quite common to see the bootloader probe for drives - which > > appears to be what is occuring in your log.) > > So you are saying that this is a grub mistake? Or should I disable cdrom/floppy > support from seabios? It's an information message. It does not indicate a problem at all. -Kevin

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Re: [SeaBIOS] Linux-ready Firmware Kit
by Peter Stuge 04 Mar '12

04 Mar '12

Fred . wrote: > Intel provides a Linux-ready Firmware Kit, available on a LiveCD Yes. > I guess it can give us a idea of the quality of the BIOS. So what were your results? //Peter

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Re: [SeaBIOS] invalid handle_legacy_disk
by Kevin O'Connor 04 Mar '12

04 Mar '12

On Fri, Mar 02, 2012 at 09:32:38AM +0100, Christian Gmeiner wrote: > What is the cause of this error message? It means an application (eg, a bootloader) called a BIOS function with an invalid parameter. It's not a SeaBIOS error condition. (Indeed, it's quite common to see the bootloader probe for drives - which appears to be what is occuring in your log.) >I am tying to boot via CFC. I'm not sure what a CFC is. -Kevin

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Re: [SeaBIOS] vgabios testing
by Kevin O'Connor 04 Mar '12

04 Mar '12

On Sun, Mar 04, 2012 at 08:08:12PM +0000, Julian Pidancet wrote: > On Sun, Mar 4, 2012 at 7:54 PM, Kevin O'Connor <kevin(a)koconnor.net> wrote: > > > > The only thing I can think of would be to post-process the assembler > > and replace "retl" instructions with "retw $2" instructions. I'm not > > sure if it would work and it would be real ugly. > > > > As I mentionned, ret is not the only instruction causing problems. > I've identified issues with leave, enter, iret, and even some forms of > the call instruction, and the list is probaly not complete yet. So it > could be even more complicated that we think. Okay. > It looks like x86emu was never tested with gcc produced code before. > And it looks like handling of the 0x66 instruction prefix has been > neglected in a lot of different places in the code. The coreboot project has an improved x86emu - it may have many of these issues fixed. -Kevin

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Re: [SeaBIOS] vgabios testing
by Kevin O'Connor 04 Mar '12

04 Mar '12

On Sun, Mar 04, 2012 at 07:26:58PM +0000, Julian Pidancet wrote: > On Sun, Mar 4, 2012 at 7:04 PM, Kevin O'Connor <kevin(a)koconnor.net> wrote: > > So, I guess the question is, how important is support for > > current/legacy x86emu versions? > > I've tried to replace .code16gcc with .code16 in src/code16gcc.s to > see if gcc would be able to generate code which doesn't use 32bit > version of the call/ret instructions. The result was quite > disappointing, it generates functions like this: That definitely wont work. Gcc assumes the return address is 32bits - it will be totally confused if it's not. (Function parameters passed on the stack wont be in the right spot.) Likely other things will break as well. > I am going to propose a patch to xorg-devel in the next few days, but > in the meantime, it would be nice to find a solution in SeaBIOS so the > code can work with older versions of Xorg. The only thing I can think of would be to post-process the assembler and replace "retl" instructions with "retw $2" instructions. I'm not sure if it would work and it would be real ugly. -Kevin

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Re: [SeaBIOS] USB boot failes
by Kevin O'Connor 04 Mar '12

04 Mar '12

On Sun, Mar 04, 2012 at 03:48:17PM +0100, Christian Gmeiner wrote: > As my last mail is still waiting for approval, I will resend it. > > Hi all, > > I am trying to boot Linux via Grub > from an USB stick. I have tried the USB stick on my devel i5 machine > and it worked. > > Log can be found here: http://nopaste.info/2b119334eb.html I don't see anything that looks obviously wrong from your log. A more detailed description of what's failing may help. Also, you could try copying the image to a machine and run it under qemu (both as an ATA image and as a USB ehci image). Testing under qemu will verify that it's not a logic error. -Kevin

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SeaBIOS March 2012