From: "Michel Dänzer" <michel@daenzer.net>
To: Christopher James Halse Rogers <christopher.halse.rogers@canonical.com>
Cc: dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 1/3] drm: Send pending vblank events before disabling vblank.
Date: Wed, 27 Apr 2011 11:08:28 +0200 [thread overview]
Message-ID: <1303895309.5633.137.camel@thor.local> (raw)
In-Reply-To: <1303894719.15750.13.camel@Ed>
On Mit, 2011-04-27 at 18:58 +1000, Christopher James Halse Rogers
wrote:
> On Wed, 2011-04-27 at 10:32 +0200, Michel Dänzer wrote:
> > On Mit, 2011-04-27 at 16:10 +1000, christopher.halse.rogers@canonical.com wrote:
> > > From: Christopher James Halse Rogers <christopher.halse.rogers@canonical.com>
> > >
> > > This is the least-bad behaviour. It means that we signal the
> > > vblank event before it actually happens, but since we're disabling
> > > vblanks there's no guarantee that it will *ever* happen otherwise.
> >
> > This may indeed be the best we can do for events that are pending when
> > the CRTC is disabled[0], but I can't see anything that would prevent new
> > events from getting scheduled (or synchronous vblank waits from timing
> > out) while the CRTC is disabled?
> >
> > [0] Though it might unnecessarily send events prematurely when the CRTC
> > is just disabled temporarily, e.g. as part of a modeset.
> >
> >
> > Also, this patch won't seem to help at all for other drivers which don't
> > call drm_vblank_off() directly when disabling a CRTC.
>
> This is true. On the other hand, the other drivers don't wedge the
> vblank code into a state where vblanks cannot be re-enabled. So it's
> only a problem when disabling one of 2+ monitors on those drivers,
And with DPMS?
> whereas it's easily triggerable on single monitor systems on intel.
Anyway, this patch is probably good at least as a preliminary fix for
the inconsistent vblank state with the intel driver.
> > Maybe it would be possible to move those calls to core code, and/or only
> > force sending out events when the CRTC isn't just getting disabled
> > temporarily.
> >
>
> As in: have the core modesetting code call drm_vblank_off before making
> the driver-specific calls when disabling a crtc? I'll look into it -
> that would appear to be a more general solution.
Yeah, something like that, thanks.
--
Earthling Michel Dänzer | http://www.vmware.com
Libre software enthusiast | Debian, X and DRI developer
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next prev parent reply other threads:[~2011-04-27 9:08 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-27 6:10 [PATCH 1/3] drm: Send pending vblank events before disabling vblank christopher.halse.rogers
2011-04-27 6:10 ` [PATCH 2/3] drm: Warn if vblank state has become inconsistent christopher.halse.rogers
2011-04-27 8:38 ` Michel Dänzer
2011-04-27 6:10 ` [PATCH 3/3] drm: Factor-out drm_emit_vblank_event code christopher.halse.rogers
2011-04-27 8:36 ` Michel Dänzer
2011-04-27 8:48 ` Christopher James Halse Rogers
2011-04-27 9:06 ` Michel Dänzer
2011-04-28 20:36 ` Jesse Barnes
2011-04-29 3:57 ` [PATCH] drm: Factor-out drm_emit_vblank_event code. (v2) christopher.halse.rogers
2011-04-29 6:43 ` Michel Dänzer
2011-04-29 15:55 ` Marcin Slusarz
2011-05-01 23:55 ` Christopher James Halse Rogers
2011-05-02 0:09 ` [PATCH] drm: Factor-out drm_emit_vblank_event code. (v3) christopher.halse.rogers
2011-04-27 8:32 ` [PATCH 1/3] drm: Send pending vblank events before disabling vblank Michel Dänzer
2011-04-27 8:58 ` Christopher James Halse Rogers
2011-04-27 9:08 ` Michel Dänzer [this message]
2011-04-27 9:17 ` Christopher James Halse Rogers
2011-04-28 8:09 ` Christopher James Halse Rogers
2011-04-28 20:46 ` Jesse Barnes
2011-04-28 20:53 ` Jesse Barnes
2011-04-28 20:42 ` Jesse Barnes
2011-04-28 20:34 ` Jesse Barnes
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