Hi,
I'm seeing an X11 crash when using the "bochs" style vga interface of SeaVGABIOS on a Fedora 13 guest. The log (see attached) shows the X server segfaulting. The crash is fully reproducible. I don't see the problem with the "lgpl vgabios". I tried various versions of qemu and SeaVGABIOS, and they all show the same crash. So, this doesn't look like a regression within SeaVGABIOS (though obviously it's a regression from the "lgpl vgabios").
It's easy to reproduce the crash - I use an installer image I have handy (Fedora-13-x86_64-DVD.iso) and run:
qemu-system-x86_64 -cdrom Fedora-13-x86_64-DVD.iso -vga std -m 512 --enable-kvm
The installer will fail to start the X server and attempt the rest of the install in text mode.
Julian - I know you played with SeaVGABIOS and X11 a bit a year or so ago. Any thoughts on what is happening?
-Kevin
On Sun, Mar 10, 2013 at 12:09 AM, Kevin O'Connor kevin@koconnor.net wrote:
Julian - I know you played with SeaVGABIOS and X11 a bit a year or so ago. Any thoughts on what is happening?
Hi Kevin,
I have not really followed the latest developments on SeaBIOS, so I'm not sure I'll be very useful. But I can try to take a look at it. I seem to remember that qemu uses SeaVGABIOS now. If I try to compile a recent qemu and launch the fedora liveCD, will it exhibit the issue ?
The last time I investigated on an issue with SeaVGABIOS and X11, it was because the 16bit code emulator of X11 wasn't handling properly certain prefixed instructions. I think we worked around the issue by post-processing the assembly output of the compilation to replace the problematic instructions with non-prefixed instructions.
I also tried to send several times a patch on the Xorg mailing list to address that issue, but never managed to attract anyone's attention. It could be useful if someone volunteered to try sending them again.
According to the backtrace you sent, the crash seems to be located in the libint10 module. The issue I worked on was in "x86emu". I'm not sure how these two parts relate to each other, but we could well be facing something very similar.
The first think I would try, is to check in the vga bios assembly and make sure we're correctly replacing all of the "sensitive" prefixed x86 instructions. Some new form of one of these instruction may have made it's way in the VGA rom code.
On Sat, Mar 09, 2013 at 07:09:01PM -0500, Kevin O'Connor wrote:
Hi,
I'm seeing an X11 crash when using the "bochs" style vga interface of SeaVGABIOS on a Fedora 13 guest.
FYI, I tested a few other fedora releases. It's broken in fc11, fc12, fc13, and fc14. It's works fine in fc15, fc16, and fc17. The fc14 logs reports "X.Org X Server v1.9.0" and fc15 reports "X.Org X Server v1.10.1". There are very few changes to the "int10" module between these official revs (git clone git://anongit.freedesktop.org/xorg/xserver ; cd xserver/hw/xfree86/int10 ), but it could be something else entirely or changes in the fedora packages.
-Kevin
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Julian Pidancet -
Kevin O'Connor