Re: [Xen-devel] [Qemu-devel] [PATCH 5/5] vga-cirrus: Workaround during restore when using Xen.

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

On Thu, Nov 24, 2011 at 18:30, Stefano Stabellini
<stefano.stabellini@xxxxxxxxxxxxx> wrote:
>
>> @@ -2784,9 +2796,11 @@ static void cirrus_reset(void *opaque)
>> Â Â Â}
>> Â Â Âs->vga.cr[0x27] = s->device_id;
>>
>> - Â Â/* Win2K seems to assume that the pattern buffer is at 0xff
>> - Â Â Â initially ! */
>> - Â Âmemset(s->vga.vram_ptr, 0xff, s->real_vram_size);
>> + Â Âif (!runstate_check(RUN_STATE_PREMIGRATE)) {
>> + Â Â Â Â/* Win2K seems to assume that the pattern buffer is at 0xff
>> + Â Â Â Â Â initially ! */
>> + Â Â Â Âmemset(s->vga.vram_ptr, 0xff, s->real_vram_size);
>> + Â Â}
>>
>
> this is not too bad, I suppose that the videoram is going to be written
> again at restore time anyway so at least it saves some cycles

Actually, I think the next time that this vram will be written again
is, when the guest is actually "waked-up" and wrote something there.
Otherwise, the "restore" of the vram is done before QEMU start. So,
the memset could leave some weard stuff the screen (a white screen?).

-- 
Anthony PERARD

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