On Wed, Jan 29, 2014 at 01:37:53PM +0200, Jani Nikula wrote: > On Wed, 29 Jan 2014, Imre Deak <[email protected]> wrote: > > schedule_timeout_uninterruptible() takes jiffies not ms. > > > > Also we should check whether jiffies has overflowed since the timestamp > > for event A was taken. This is highly unlikely on 64 bit, but on 32 bit > > machines jiffies initially is -300*HZ. If the panel power is initially > > off the first wait from edp_panel_vdd_on()->wait_panel_power_cycle() > > will result in a call timestamp_jiffies of 0, so on 32 bit machines we > > would wait ~300 sec + to_wait_ms. Fix this by checking if the initial > > timestamp is not in the future. > > > > Signed-off-by: Imre Deak <[email protected]> > > --- > > drivers/gpu/drm/i915/i915_drv.h | 17 +++++++++-------- > > 1 file changed, 9 insertions(+), 8 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/i915_drv.h > > b/drivers/gpu/drm/i915/i915_drv.h > > index 3673ba1..6a80393 100644 > > --- a/drivers/gpu/drm/i915/i915_drv.h > > +++ b/drivers/gpu/drm/i915/i915_drv.h > > @@ -2643,12 +2643,13 @@ timespec_to_jiffies_timeout(const struct timespec > > *value) > > * doesn't happen exactly after event A, you record the timestamp > > (jiffies) of > > * when event A happened, then just before event B you call this function > > and > > * pass the timestamp as the first argument, and X as the second argument. > > + * Note that the recorded timestamp (timestamp_jiffies) can't be in the > > future > > + * otherwise the function won't wait at all. > > */ > > static inline void > > wait_remaining_ms_from_jiffies(unsigned long timestamp_jiffies, int > > to_wait_ms) > > { > > - unsigned long target_jiffies, tmp_jiffies; > > - unsigned int remaining_ms; > > + unsigned long target_jiffies, tmp_jiffies, remaining_jiffies; > > > > /* > > * Don't re-read the value of "jiffies" every time since it may change > > @@ -2658,12 +2659,12 @@ wait_remaining_ms_from_jiffies(unsigned long > > timestamp_jiffies, int to_wait_ms) > > target_jiffies = timestamp_jiffies + > > msecs_to_jiffies_timeout(to_wait_ms); > > > > - if (time_after(target_jiffies, tmp_jiffies)) { > > - remaining_ms = jiffies_to_msecs((long)target_jiffies - > > - (long)tmp_jiffies); > > - while (remaining_ms) > > - remaining_ms = > > - schedule_timeout_uninterruptible(remaining_ms); > > + if (time_after(target_jiffies, tmp_jiffies) && > > + time_before_eq(timestamp_jiffies, tmp_jiffies)) { > > + remaining_jiffies = target_jiffies - tmp_jiffies; > > + while (remaining_jiffies) > > + remaining_jiffies = > > + schedule_timeout_uninterruptible(remaining_jiffies); > > } > > } > > For the record, I spotted the jiffies vs. ms mistake in review [1], > Paulo posted v5 [2], but apparently Daniel applied v4 anyway: > > commit dce56b3c626fb1d533258a624d42a1a3fc17da17 > Author: Paulo Zanoni <[email protected]> > Date: Thu Dec 19 14:29:40 2013 -0200 > > drm/i915: save some time when waiting the eDP timings > > Wrap around was also discussed. > > > BR, > Jani. > > [1] http://mid.gmane.org/[email protected] > [2] http://mid.gmane.org/[email protected]
Oh dear, I'll hide in shame. Dunno how I've botched this one up, thanks for catching it. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
