On 04/11/2015 08:26, Axel Davy wrote:
On 04/11/2015 04:17, Michel Dänzer wrote:
On 03.11.2015 17:14, Axel Davy wrote:
+ } else if (target_msc == crtc_msc &&
+ (options & PresentOptionAsync) &&
+ (screen_priv->info->capabilities &
PresentCapabilityAsync) &&
+ present_check_flip (target_crtc, window, pixmap, FALSE,
valid, x_off, y_off))
+ {
+ vblank->flip = TRUE;
+ }
Why only take this case if target_msc == crtc_msc?
At this point of the code, when we have (option & PresentOptionAsync),
target_msc >= crtc_msc
If target_msc > crtc_msc, then we want to use a sync flip (An async
flip can cause tears),
and we use the previous if statement.
But in the case target_msc == crtc_msc, we want to copy immediately
(via an async flip, or a copy).
I realize that the "(option & PresentOptionAsync)" part of the check
is unneccessary.
I guess in the case the driver has disabled sync swaps, we want to use
async swaps instead of copies.
Thus the target_msc == crtc_msc can be replaced by target_msc >=
crtc_msc (always true)
in that case the if check becomes:
else if ((screen_priv->info->capabilities & PresentCapabilityAsync) &&
present_check_flip (target_crtc, window, pixmap, FALSE,
valid, x_off, y_off)
Yours,
Axel
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