[Intel-gfx] [(resend) PATCH 1/2] drm/i915: Calculate vlv/chv intermediate watermarks correctly, v3.

[Maarten Lankhorst]

Op 17-11-17 om 15:53 schreef Ville Syrjälä:
> On Fri, Nov 17, 2017 at 03:47:58PM +0100, Maarten Lankhorst wrote:
>> Op 17-11-17 om 14:31 schreef Ville Syrjälä:
>>> On Wed, Nov 15, 2017 at 05:31:56PM +0100, Maarten Lankhorst wrote:
>>>> The watermarks it should calculate against are the old optimal watermarks.
>>>> The currently active crtc watermarks are pure fiction, and are invalid in
>>>> case of a nonblocking modeset, page flip enabling/disabling planes or any
>>>> other reason.
>>>>
>>>> When the crtc is disabled or during a modeset the intermediate watermarks
>>>> don't need to be programmed separately, and could be directly assigned
>>>> to the optimal watermarks.
>>>>
>>>> CXSR must always be disabled in the intermediate case for modesets, else
>>>> we get a WARN for vblank wait timeout.
>>>>
>>>> Also rename crtc_state to new_crtc_state, to distinguish it from the old state.
>>>>
>>>> Changes since v1:
>>>> - Use intel_atomic_get_old_crtc_state. (ville)
>>>> Changes since v2:
>>>> - Always unset cxsr during modeset.
>>>>
>>>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
>>> I was going to try and figure out how/if these get rid of the unclaimed
>>> reg warns, but I didn't quite get that far. I did spot a few other
>>> buglets in the wm code though (I'll send fixes for those at some point).
>>>
>>> Anyways, these patches make sense to me, so for the series
>>> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>> Seems Chris Wilson already beat us to it..
>>
>> https://intel-gfx-ci.01.org/tree/drm-tip/igt@kms_pipe_crc_basic@suspend-read-crc-pipe-b.html
>> was gone with
>>
>> commit 1a1f12872edcd5e425b668a35fb23548cfa918ef
>> Author: Chris Wilson <chris at chris-wilson.co.uk <mailto:chris at chris-wilson.co.uk>>
>> Date:   Tue Nov 7 14:03:38 2017 +0000
>>
>>     drm/i915: Prevent unbounded wm results in g4x_compute_wm()
> That patch should be nop. So this is a very surprising result.
>
Oh well maybe the watermarks initially read out were being garbage. Garbage in, garbage out. :-)