Re: [Qemu-devel] [Xen-devel] [RFC PATCH] vga: Start supporting resolution not multiple of 16 correctly.

[Pasi Kärkkäinen]

On Sun, Jul 28, 2013 at 05:56:01PM +0100, Frediano Ziglio wrote:
>    2013/7/23 Gerd Hoffmann <address@hidden>
> 
>      Â  Hi,
>      > Tested-by: Fabio Fantoni <address@hidden>
>      >
>      > I tested it for a long time with spice on xen (because qxl will be
>      fully
>      > working only after adding SSE support on hvm domUs). It works, I think
>      > it is good to add this and the respective vgabios patch on upstream.
> 
>      >> Â  Â  Â  Â  Â case VBE_DISPI_INDEX_XRES:
>      >> - Â  Â  Â  Â  Â  Â if ((val <= VBE_DISPI_MAX_XRES) && ((val & 7) ==
>      0)) {
>      >> + Â  Â  Â  Â  Â  Â if ((val <= VBE_DISPI_MAX_XRES) && ((val & 1) ==
>      0)) {
>      >> Â  Â  Â  Â  Â  Â  Â  Â  Â s->vbe_regs[s->vbe_index] = val;
>      >> Â  Â  Â  Â  Â  Â  Â }
>      >> Â  Â  Â  Â  Â  Â  Â break;
> 
>      It's not that simple. Â With 32bit depths common today it will work
>      fine,
>      but for lower depths (especially those lower than 8bit) this will give
>      you broken scanline alignment.
> 
>      cheers,
>      Â  Gerd
> 
>    In the card I tested the scanline is keep aligned but for this reason is
>    not directly computed by maxx * bits but is something bigger.
>

Hmm.. so is an update needed for this patch? It'd be nice to get this patch in!


-- Pasi
 
>    Frediano
>