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cirrus-vga is not properly reset

DISCUSSION Jan Kiszka 1 participant 2 messages Jan 17, 2009 KVM

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Jan Kiszka

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Hi,

when rebooting from non-text mode, the text output of BIOS and bootloader is unreadable. This only happens with cirrus and the KVM tree, std-vga is fine, cirrus with upstream QEMU is fine, too. Moreover, -no-kvm makes no difference.

What's very strange about this: CirrusVGAState does not differ after issuing a reset from text mode compared to a reset from graphic mode (except for a needless re-init of some io_memory slots - will post a cleanup patch upstream). Currently I have no clue where to look next.

Jan

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Quoted 6 lines · Jan Kiszka

Hi,

when rebooting from non-text mode, the text output of BIOS and bootloader is unreadable. This only happens with cirrus and the KVM tree, std-vga is fine, cirrus with upstream QEMU is fine, too. Moreover, -no-kvm makes no difference.

Looked at it again, and I was able to reproduce this problem with latest QEMU, too. It just doesn't trigger that reliably as with kvm-userspace.

So I bet it has something to do with recent QEMU reset changes for vga and cirrus (the display changes are not yet merged into kvm, so they can't contribute to the reason). Moreover, the error pattern suggests that correct text is written to the VGA RAM and attempted to dump to the screen, but the font that should have been written to VGA RAM by the BIOS is corrupted.

Quoted 8 lines

What's very strange about this: CirrusVGAState does not differ after issuing a reset from text mode compared to a reset from graphic mode (except for a needless re-init of some io_memory slots - will post a cleanup patch upstream). Currently I have no clue where to look next.

Jan

Jan