[PATCH v2] Handle failures in setting a CRTC to a DRM mode properly

[Michel Dänzer]

On 26.10.2015 20:01, Emil Velikov wrote:
> On 26 October 2015 at 10:55, Daniel Martin <consume.noise at gmail.com> wrote:
>> On 26 October 2015 at 10:39, Michel Dänzer <michel at daenzer.net> wrote:
>>>> diff --git a/src/drmmode_display.c b/src/drmmode_display.c
>>>> index 64e79d4..f0f121e 100644
>>>> --- a/src/drmmode_display.c
>>>> +++ b/src/drmmode_display.c
>>>> @@ -760,12 +760,15 @@ drmmode_set_mode_major(xf86CrtcPtr crtc, DisplayModePtr mode,
>>>>                               radeon_bo_wait(drmmode_crtc->scanout[0].bo);
>>>>                       }
>>>>               }
>>>> -             ret = drmModeSetCrtc(drmmode->fd, drmmode_crtc->mode_crtc->crtc_id,
>>>> -                                  fb_id, x, y, output_ids, output_count, &kmode);
>>>> -             if (ret)
>>>> +             if (drmModeSetCrtc(drmmode->fd,
>>>> +                                drmmode_crtc->mode_crtc->crtc_id,
>>>> +                                fb_id, x, y, output_ids,
>>>> +                                output_count, &kmode) != 0) {
>>>>                       xf86DrvMsg(crtc->scrn->scrnIndex, X_ERROR,
>>>>                                  "failed to set mode: %s", strerror(-ret));
>>>
>>> errno must be passed instead of -ret to strerror. I pushed the patch
>>> with that fixed, thanks!
>>
>> While you're at it, can you add the missing linebreak to the message?
>> Just hit it and it looks suspicious:
>>     (EE) modeset(0): failed to set mode: Invalid argument(--) RandR disabled
>> or
>>     (EE) modeset(0): failed to set mode: Invalid argument(II)
>> modeset(0): Setting screen physical size to 677 x 381
>>
> Mildly related:
>  - Using -ret opposed to errno -> intel, nouveau, modeset ddx

The -ret => errno change is only necessary because we're no longer
assigning the return value of drmModeSetCrtc (which is -errno) to ret.
This doesn't apply to intel or nouveau (or to modesetting without the
fix above).


>  - Incorrectly handled failure and missing \n -> modeset ddx

Yep, in fact Daniel is using the modesetting driver, not radeon.

Patches welcome for both cases. :)


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