EPIA-M serial port 1/2 baud rate insanity

[Dave Ashley]

I am at my wits end regarding how to get the serial ports on the epia-m to
run at full 115,200 baud rate. Here is a summary of what is known:

1) The serial ports are driven by the VT1211 superio chip.
2) Under AWARD bios the serial ports are capable of 115,200 operation.
3) Under linuxbios they can only run at 57,600 max.
4) Booting up with AWARD then soft reset (or hit reset button on motherboard)
into linuxbios still maintains 115,200 baud
5) Hard reset (power off then on) into linuxbios reduces maximum baud rate to
57,600.
6) All registers of the VT1211 are identical after linuxbios bootup, whether
from award -> softreset -> linuxbios bootup or hardreset -> linuxbios bootup.
I am speaking of all registers of all logical devices of the VT1211, including
all the global registers. I wrote a program to dump everything then diff'd the
two outputs, they're identical.

I have repeatedly tried asking VIA for help, in various different ways. The
VT1211 datasheet and the VT1211 bios porting guide have not resolved the
issue. VIA has proven incapable of addressing the problem.

I have one last idea. There is an emulator to test VGA bios's, I was messing
with it a few months back. Is there an emulator for the full BIOS? I'd like
to be able to watch all io port accesses of the award bios, maybe I can
trap when it goes to write to the 0x2e + 0x2f io ports to configure the
vt1211 serial ports, then look for something near there that might be related.
The idea would be to figure out what magical thing the AWARD bios is doing
to initialize the serial port.

Failing that is there any way to disassemble a BIOS image?

Any ideas welcome.

BTW if anyone has figured out how to fix the problem, please just f*cking
out with it, I think I've been very generous in the past with enhancements
and turnabout is fair play.

Thanks--
Dave

EPIA-M serial port 1/2 baud rate insanity [PMX:#]

[ron minnich]

I don't know what the problem is, I don't have an EPIA-M yet.

One thing you could do with a PCI analyzer is watch the ins and outs and 
look for a magic setting.

Are your sure the clock source for the superio or uart is the same for 
linuxbios and award?

disassembly is a bad idea.

The "emulator for VGA bios" will actually run anything that looks like a 
bios. I've run T23 bios on a T23 (and crashed the T23 that way). So that 
works.

ron

[Andrew Ip]

Hi Dave,

Have you checked out the clock connected to LPC?  On W311, FS2 can be
set to 24 or 48 MHz.  It could be the problem, since I have similar problem
with USB on a custom cle266 board.  FYI, it can be programmed thru smb.  
Here is from we have done to program the USB clock.

#define  SMB_BASE_ADDRESS    0x5000

#define  SMB_STATUS             (SMB_BASE_ADDRESS + 0)
#define  SMB_CONTROL            (SMB_BASE_ADDRESS + 2)
#define  SMB_COMMAND            (SMB_BASE_ADDRESS + 3)
#define  SMB_ADDRESS            (SMB_BASE_ADDRESS + 4)
#define  SMB_DATA               (SMB_BASE_ADDRESS + 5)

#define  I2C_TRANS_CMD                  0x40
#define  CLOCK_SLAVE_ADDRESS    0x69

static void ext_clock_fixup(void)
{
        int dt;
        struct pci_dev *dev;

dev = pci_find_device(PCI_VENDOR_ID_VIA, 0x3177, 0);
        if (dev != NULL)
        {
                printk_info("ext clock setting\n");

//  SMB IO address 5000h
                pci_write_config_byte(dev, 0xD1, (SMB_BASE_ADDRESS>>8)&0xff );
                pci_write_config_byte(dev, 0xD0, SMB_BASE_ADDRESS&0xff );
                //  enable SMB
                pci_write_config_byte(dev, 0xD2, 0x01);

// clear status
                outb( 0xff, SMB_STATUS );

// USB out 48MHz
                outb( 0x7f, SMB_DATA );
                outb( 0x83, SMB_COMMAND );
                outb( (CLOCK_SLAVE_ADDRESS<<1), SMB_ADDRESS );
                outb( 0x8|I2C_TRANS_CMD, SMB_CONTROL );

while( inb(SMB_STATUS) & 0x01 );
        }

}

You may want to put similar code in serial init.  Hope this help.

-Andrew

On Wed, Dec 17, 2003 at 11:13:02AM -0800, Dave Ashley wrote:
> I am at my wits end regarding how to get the serial ports on the epia-m to
> run at full 115,200 baud rate. Here is a summary of what is known:
> The serial ports are driven by the VT1211 superio chip.
> Under AWARD bios the serial ports are capable of 115,200 operation.
> Under linuxbios they can only run at 57,600 max.
> Booting up with AWARD then soft reset (or hit reset button on motherboard)
>
> into linuxbios still maintains 115,200 baud
> 5) Hard reset (power off then on) into linuxbios reduces maximum baud rate to
> 57,600.
> 6) All registers of the VT1211 are identical after linuxbios bootup, whether
> from award -> softreset -> linuxbios bootup or hardreset -> linuxbios bootup.
> I am speaking of all registers of all logical devices of the VT1211, including
> all the global registers. I wrote a program to dump everything then diff'd the
> two outputs, they're identical.
>
> I have repeatedly tried asking VIA for help, in various different ways. The
> VT1211 datasheet and the VT1211 bios porting guide have not resolved the
> issue. VIA has proven incapable of addressing the problem.
>
> I have one last idea. There is an emulator to test VGA bios's, I was messing
> with it a few months back. Is there an emulator for the full BIOS? I'd like
> to be able to watch all io port accesses of the award bios, maybe I can
> trap when it goes to write to the 0x2e + 0x2f io ports to configure the
> vt1211 serial ports, then look for something near there that might be related.
> The idea would be to figure out what magical thing the AWARD bios is doing
> to initialize the serial port.
>
> Failing that is there any way to disassemble a BIOS image?
>
> Any ideas welcome.
>
> BTW if anyone has figured out how to fix the problem, please just f*cking
> out with it, I think I've been very generous in the past with enhancements
> and turnabout is fair play.
>
> Thanks--
> Dave
>
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