[PATCH] fb: Correctly implement CopyArea when using a window with depth 32 and 24bpp.

[Alex Deucher]

On Thu, Aug 7, 2014 at 8:45 AM, Takashi Iwai <tiwai at suse.de> wrote:
> At Fri, 6 Jun 2014 23:59:20 +1200,
> Robert Ancell wrote:
>>
>> This fixes gnome-terminal not showing in qemu [1] and can be triggered
>> by the attached test case.
>>
>> I haven't combined this with the patch in [2] because this patch is
>> internally coherent with the fb logic; I still don't know if fb is
>> doing the right thing here by allowing depth=32 bpp=24. The RENDER
>> patch is not required for gnome-terminal (and I suspect any
>> application using depth 32 visual and cairo/GTK+ to render) but
>> follows the same logic.
>>
>> --Robert
>>
>> [1] http://lists.x.org/archives/xorg-devel/2014-June/042723.html
>> [2] http://lists.x.org/archives/xorg-devel/2014-June/042721.html
>
> I confirm that this patch fixes the problem on QEMU cirrus.
>
> Tested-by: Takashi Iwai <tiwai at suse.de>
>
> Can anyone review and take?  It's been a very long-standing and
> annoying problem over years.

Seems reasonable to me.

Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

>
>
> Thanks!
>
> Takashi
>
>
>>
>> On Fri, Jun 6, 2014 at 11:52 PM, Robert Ancell
>> <robert.ancell at canonical.com> wrote:
>> > When using the fb backend at 24bpp it allows a visual with 32 bit depth.
>> > When using CopyArea from a 32bpp pixmap to a window with a 32 bit depth it would
>> > read the ARGB as RGB.
>> >
>> > Fix is to correctly ignore the alpha channel in the pixmap when copying.
>> > ---
>> >  fb/fbcopy.c | 10 +++++++++-
>> >  1 file changed, 9 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/fb/fbcopy.c b/fb/fbcopy.c
>> > index 541ef71..5455947 100644
>> > --- a/fb/fbcopy.c
>> > +++ b/fb/fbcopy.c
>> > @@ -242,8 +242,16 @@ fbCopyArea(DrawablePtr pSrcDrawable,
>> >             int xIn, int yIn, int widthSrc, int heightSrc, int xOut, int yOut)
>> >  {
>> >      miCopyProc copy;
>> > +    int src_bpp, dst_bpp;
>> >
>> > -    if (pSrcDrawable->bitsPerPixel != pDstDrawable->bitsPerPixel)
>> > +    src_bpp = pSrcDrawable->bitsPerPixel;
>> > +    if (src_bpp < pSrcDrawable->depth)
>> > +        src_bpp = BitsPerPixel (pSrcDrawable->depth);
>> > +    dst_bpp = pDstDrawable->bitsPerPixel;
>> > +    if (dst_bpp < pDstDrawable->depth)
>> > +        dst_bpp = BitsPerPixel (pDstDrawable->depth);
>> > +
>> > +    if (src_bpp != dst_bpp)
>> >          copy = fb24_32CopyMtoN;
>> >      else
>> >          copy = fbCopyNtoN;
>> > --
>> > 2.0.0
>> >
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