[PATCH v4 02/13] modesetting: scanout_pixmap_gpu one call only

[Michel Dänzer]

On 04.03.2016 11:47, Alex Goins wrote:
> Subsequent commits will involve multiple calls to
> rrCrtcSetScanoutPixmap(ppix) without a call to rrCrtcSetScanoutPixmap(NULL)
> in between. This causes drmmode_set_scanout_pixmap_gpu() to track damage
> multiple times but ultimately only stop tracking on one, which could lead
> to dangling pointers.
> 
> I don't intend to support PRIME synchronization with reverse PRIME at this
> time, so just fail in this case.
> 
> It's probably a bad idea to rely on randr setting
> randr_crtc->scanout_pixmap in order to know which pixmap to stop damage
> tracking on, but I'll keep it that way for now to stay consistent.
> 
> v1: N/A
> v2: N/A
> v3: N/A
> v4: Initial commit
> 
> Signed-off-by: Alex Goins <agoins at nvidia.com>
> ---
>  hw/xfree86/drivers/modesetting/drmmode_display.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/hw/xfree86/drivers/modesetting/drmmode_display.c b/hw/xfree86/drivers/modesetting/drmmode_display.c
> index 0d34ca1..ed67dbe 100644
> --- a/hw/xfree86/drivers/modesetting/drmmode_display.c
> +++ b/hw/xfree86/drivers/modesetting/drmmode_display.c
> @@ -586,6 +586,11 @@ drmmode_set_scanout_pixmap_gpu(xf86CrtcPtr crtc, PixmapPtr ppix)
>          drmmode_crtc->prime_pixmap_x = 0;
>          return TRUE;
>      }
> +
> +    /* Currently supports only one scanout pixmap */
> +    if (crtc->randr_crtc->scanout_pixmap)
> +        return FALSE;
> +
>      /* iterate over all the attached crtcs to work out the bounding box */
>      for (c = 0; c < xf86_config->num_crtc; c++) {
>          xf86CrtcPtr iter = xf86_config->crtc[c];
> 

AFAICT RRReplaceScanoutPixmap may call set_scanout_pixmap while
randr_crtc->scanout_pixmap is already non-NULL (and pointing to a
different pixmap). Are you saying that only happens in the reverse PRIME
case?


(All my hardware requires reverse PRIME, so I still can't test this
series unfortunately)


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer