[PATCH xserver] modesetting: Properly cleanup fb for reverse-prime-offload

[Michel Dänzer]

On 22.06.2016 12:47, Michel Dänzer wrote:
> On 02.06.2016 04:04, Hans de Goede wrote:
>> drmmode_set_scanout_pixmap_gpu(pix) adds drmmod->fb_id through a call
>> to drmmode_xf86crtc_resize(), but on a subsequent
>> drmmode_set_scanout_pixmap_gpu(NULL) it would not remove the fb.
>>
>> This keeps the crtc marked as busy, which causes the dgpu to not
>> being able to runtime suspend, after an output attached to the dgpu
>> has been used once. Which causes burning through an additional 10W
>> of power and the laptop to run quite hot.
>>
>> This commit adds the missing remove fb call, allowing the dgpu to runtime
>> suspend after an external monitor has been plugged into the laptop.
>>
>> Note this also makes drmmode_set_scanout_pixmap_gpu(NULL) match the
>> behavior of drmmode_set_scanout_pixmap_cpu(NULL) which was already
>> removing the fb.
>>
>> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
>> ---
>>  hw/xfree86/drivers/modesetting/drmmode_display.c | 8 +++++++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/xfree86/drivers/modesetting/drmmode_display.c b/hw/xfree86/drivers/modesetting/drmmode_display.c
>> index 5b90369..4c55c4e 100644
>> --- a/hw/xfree86/drivers/modesetting/drmmode_display.c
>> +++ b/hw/xfree86/drivers/modesetting/drmmode_display.c
>> @@ -643,11 +643,17 @@ drmmode_set_scanout_pixmap_gpu(xf86CrtcPtr crtc, PixmapPtr ppix)
>>      PixmapPtr screenpix = screen->GetScreenPixmap(screen);
>>      xf86CrtcConfigPtr xf86_config = XF86_CRTC_CONFIG_PTR(crtc->scrn);
>>      drmmode_crtc_private_ptr drmmode_crtc = crtc->driver_private;
>> +    drmmode_ptr drmmode = drmmode_crtc->drmmode;
>>      int c, total_width = 0, max_height = 0, this_x = 0;
>>  
>>      if (!ppix) {
>> -        if (crtc->randr_crtc->scanout_pixmap)
>> +        if (crtc->randr_crtc->scanout_pixmap) {
>>              PixmapStopDirtyTracking(crtc->randr_crtc->scanout_pixmap, screenpix);
>> +            if (drmmode->fb_id) {
>> +                drmModeRmFB(drmmode->fd, drmmode->fb_id);
>> +                drmmode->fb_id = 0;
>> +            }
>> +        }
> 
> Can't drmmode->fb_id still be needed for other CRTCs?

I did some experiments, and AFAICT this drmModeRmFB call will turn off
all CRTCs which are currently scanning out from the removed framebuffer.
Is there code which re-enables any other CRTCs which are still supposed
to be on?


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