[Mesa-dev] [PATCH] egl/x11: Send invalidate to the driver on dri2_copy_region

[Thomas Hellstrom]

On 04/26/2018 10:30 AM, Michel Dänzer wrote:
> On 2018-04-25 07:49 PM, Deepak Rawat wrote:
>> Similar to what is done in dri2_x11_swap_buffers_msc send invalidate
>> to the driver because egl/X11 is not watching for for server's
>> invalidate events. The dri2_copy_region path is trigerred when
>> server supports DRI2 version minor 1.
>>
>> Tested with piglit egl tests for regression.
>>
>> Cc: <mesa-stable at lists.freedesktop.org>
>> Signed-off-by: Deepak Rawat <drawat at vmware.com>
>> Reviewed-by: Thomas Hellstrom <thellstrom at vmware.com>
>> ---
>>   src/egl/drivers/dri2/platform_x11.c | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/src/egl/drivers/dri2/platform_x11.c b/src/egl/drivers/dri2/platform_x11.c
>> index 6c287b4d06..e99434ea3a 100644
>> --- a/src/egl/drivers/dri2/platform_x11.c
>> +++ b/src/egl/drivers/dri2/platform_x11.c
>> @@ -841,6 +841,13 @@ dri2_copy_region(_EGLDriver *drv, _EGLDisplay *disp,
>>   					   render_attachment);
>>      free(xcb_dri2_copy_region_reply(dri2_dpy->conn, cookie, NULL));
>>   
>> +   /*
>> +    * Just like as done in dri2_x11_swap_buffers_msc we aren't watching for
>> +    * server's invalidate events, so just send invalidate to driver.
>> +    */
>> +   if (dri2_dpy->flush->base.version >= 3 && dri2_dpy->flush->invalidate)
>> +      dri2_dpy->flush->invalidate(dri2_surf->dri_drawable);
>> +
>>      return EGL_TRUE;
>>   }
> Why is invalidate needed after copy_region? That's surprising, I suspect
> it just papers over the real problem.
>
>
I had a quick look into the platform_x11 code. dri2_copy_region is 
called only from the various swap_buffers() paths, 
dri2_x11_swap_buffers() and dri2_x11_swap_buffers_region(). Explicit 
invalidation is, before this patch, done only if the server supports 
dri2 swaps. Probably because most drivers do, vmware does not, so we can 
hit swapbuffers without doing explicit invalidation.

In comparison, GLX does explicit invalidation on swapbuffers, 
bind_context and bind_texture for the same protocol version, so this 
patch should only bring the EGL swapbuffer paths closer to what GLX is 
doing, while still not addressing bind_context and bind_texture.

FWIW, EGL platform_x11 (dri2) seems to not parse server invalidate 
events for the higher protocol versions, relying solely on explicit 
invalidation.

/Thomas