[PATCH] Disable CRTCs when disabling the outputs

[Michel Dänzer]

On 23.06.2015 04:19, Piotr Redlewski wrote:
> 
> 
> 2015-06-22 12:01 GMT+02:00 Piotr Redlewski <predlewski at gmail.com
> <mailto:predlewski at gmail.com>>:
> 
> 
> 
>     2015-06-22 9:49 GMT+02:00 Michel Dänzer <michel at daenzer.net
>     <mailto:michel at daenzer.net>>:
> 
>         On 21.06.2015 23 <tel:21.06.2015%2023>:30, Piotr Redlewski wrote:
>         > When turning the outputs off (DPMSModeOff), CRTCs stayed enabled. This led
>         > to higher card temperatures than with fglrx driver.
>         >
>         > Signed-off-by: Piotr Redlewski <predlewski at gmail.com <mailto:predlewski at gmail.com>>
>         > ---
>         >  src/drmmode_display.c | 9 ++++++++-
>         >  1 file changed, 8 insertions(+), 1 deletion(-)
>         >
>         > diff --git a/src/drmmode_display.c b/src/drmmode_display.c
>         > index 3564853..04b4341 100644
>         > --- a/src/drmmode_display.c
>         > +++ b/src/drmmode_display.c
>         > @@ -342,7 +342,14 @@ drmmode_do_crtc_dpms(xf86CrtcPtr crtc, int mode)
>         >  static void
>         >  
>         ​​
>         drmmode_crtc_dpms(xf86CrtcPtr crtc, int mode)
>         >  {
>         > -     /* Nothing to do. drmmode_do_crtc_dpms() is called as appropriate */
>         > +     drmmode_crtc_private_ptr drmmode_crtc = crtc->driver_private;
>         > +     drmmode_ptr drmmode = drmmode_crtc->drmmode;
>         > +
>         > +     /* Disable unused CRTCs */
>         > +     if (!crtc->enabled && mode != DPMSModeOn) {
> 
>         Maybe this should be
> 
>                 if (!crtc->enabled || mode != DPMSModeOn) {
> 
>         or can it actually happen that
>         ​​
>         !crtc->enabled and mode == DPMSModeOn?
> 
>     ​Just wanted to be safe here, but I think you are right. I'll send
>     v2 later today.
> 
> ​I wanted to test changes before sending v2 and I stumbled on one issue.
> Everything works as expected when xrandr is used, but problem starts
> when screensaver 
> ​comes into play. X calls 
> drmmode_crtc_dpms() to on/off screensaver, so when it is supposed to be
> enabled, function is called with mode=DPMSModeOff and we
> call drmModeSetCrtc() to set crtc's mode to NULL. Problem is when X
> wants to disable screensaver: drmmode_crtc_dpms() is called with
> mode=DPMSModeOn and... nothing happens as there is no logic for this
> scenario - we should call drmModeSetCrtc() to set valid mode, but we
> don't know what this mode should be.

Isn't crtc->mode valid at that point?

If it's not, maybe we can store the mode in drmmode_crtc and use that
instead.


> ​Because of the situation with the screensaver I think that original
> version of the patch is ok (it solves the problem with CRTC staying
> enabled when using xrandr to disable the output).

It would be nice to get the same effect for DPMS off though, wouldn't it?


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