Re: [Qemu-devel] Regression: more 0.12 regression (SeaBIOS related?)

[Roy Tam <roytam@gmail.com>]

2010/3/10 Kevin O'Connor <kevin@koconnor.net>:
> On Wed, Mar 10, 2010 at 11:49:48AM +0800, Roy Tam wrote:
>> 2010/3/10 Kevin O'Connor <kevin@koconnor.net>:
>> > SeaBIOS has a wealth of debugging information that could help solve
>> > these issues.
>>
>> Tried this this BIOS and 2 debug logs generated.
>> seabios-debug.log is booting fdos0138.img and closes QEMU after boots to prompt.
>> seabios-debug-2.log is booting fdos0138.img and type something and
>> Illegal Instruction occurred.
>
> I don't see an "Illegal Instruction" message.  Instead, I see the
> keyboard just not working.  What qemu version and what command line
> did you use?
>
> I've tracked down why keys are lost on SeaBIOS and not lost on Bochs
> BIOS.  The fdos0138.img code is taking over the irq handler for the
> ps2 port hardware irq.  When the irq fires, it reads the ps2 port for
> the key data and then calls the bios irq handler assuming it will
> reread the key and process it.  However, SeaBIOS reads the ps2 port
> status indicator and finds that there is no data pending (because the
> key was already read by the fdos0138.img irq handler).
>
> Bochs BIOS just reads the data from the ps2 port and assumes it is for
> the keyboard.  SeaBIOS verifies the data being read and wont process
> random data from the port.
>
> What the fdos0138.img image is doing is broken - once it reads the key
> from the ps2 port, nothing stops a new key from being read the next
> time something reads from the port.  Indeed, although the keyboard
> works in qemu-0.11 for fdos0138.img, if one types fast they'll see
> duplicate and lost keys.
>
>> >> http://www.drdosprojects.de/cgi-bin/download.cgi/d090723b.zip
>
> This image fails in the same way on both qemu-0.11 and qemu-0.12, so I
> don't think it's a seabios issue.

You have to use MAKEBOOT.BAT to create a boot floppy (you can do it
inside QEMU to write it into an image too.)

>
> -Kevin
>