[openchrome-devel] [PATCH/RFT v1 0/6] drm/via: drop use of deprecated headers drmP.h and drm_os_linux.h

[Michel Dänzer]

On 2019-07-19 8:07 a.m., Sam Ravnborg wrote:
> On Thu, Jul 18, 2019 at 05:37:31PM +0200, Sam Ravnborg wrote:
>> This is some janitorial updates to the via driver
>> that is required to get rid of deprecated headers
>> in the drm subsystem.
>>
>> The first three patches are trivial, where
>> the dependencies on drmP.h and drm_os_linux are dropped.
>>
>> The remaining three patches drop use of DRM_WAIT_ON().
>> They are replaced by wait_event_interruptible_timeout().
>> These patches could use a more critical review.
> 
> The differences between DRM_WAIT_ON() and
> wait_event_interruptible_timeout() are bigger than anticipated.
> 
> The conversion I did for drm_vblank.c is bogus thus I expect
> the conversion done for via is also bogus.

What exactly is the problem though? Can you share information about the
failures you're seeing?

There was some discussion about DRM_WAIT_ON() "polling" on IRC. I assume
that refers to it only sleeping for up to 0.01s before checking the
condition again. In contrast, wait_event_interruptible_timeout() checks
the condition once, then sleeps up to the full timeout before checking
it again.

If that makes a difference for drm_wait_vblank_ioctl, it indicates that
some other code which updates the vblank count or clears vblank->enabled
doesn't wake up the vblank->queue.


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