Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 3 Feb 2011 16:30:56 -0800 | Subject | Re: 2.6.38-rc3-git1: Reported regressions 2.6.36 -> 2.6.37 |
| |
On Thu, Feb 3, 2011 at 4:06 PM, Dave Airlie <airlied@gmail.com> wrote: > > If we are setting a mode on a connector it automatically will end up > in a DPMS on state, > so this seemed correct from what I can see.
The more I look at that function, the more I disagree with you and with that patch.
The code is just crazy.
First off, it isn't even necessarily setting a mode to begin with, because as far as I can tell. If the mode doesn't change, neither mode_changed nor fb_changed will be true, afaik. There seems to be a fair amount of code there explicitly to avoid changing modes if not necessary.
But even _if_ we are setting a mode, if I read the code correctly, the mode may be set to NULL - which seems to mean "turn it off". In which case it looks to me that drm_helper_disable_unused_functions() will actually do a
(*crtc_funcs->dpms)(crtc, DRM_MODE_DPMS_OFF);
call on the crtc in question. So then blindly just saying "it's mode DRM_MODE_DPMS_ON" afterwards looks rather bogus to me.
_Maybe_ it would work if it was done before that whole "disable_unused" logic. Or maybe it should just be done in drm_crtc_helper_set_mode(), which is what actually sets the mode (but there's the 'fb_changed' case too)
> A future mode set shouldn't ever not turn the connector on, since > modesetting is an implicit > DPMS, > > It sounds like something more subtle than that, though I'm happy to > revert this for now, and let Keith > think about it a bit more.
So I haven't heard anything from Keith. Keith? Just revert it? Or do you have a patch for people to try?
Linus
| |