[Intel-gfx] [PATCH (resend) 1/3] drm/i915: Ignore previous watermarks on ILK if inherited

[Maarten Lankhorst]

Op 09-11-17 om 11:41 schreef Daniel Vetter:
> On Wed, Nov 08, 2017 at 05:09:33PM +0100, Maarten Lankhorst wrote:
>> Op 08-11-17 om 16:41 schreef Daniel Vetter:
>>> On Wed, Nov 08, 2017 at 10:29:20AM +0100, Maarten Lankhorst wrote:
>>>> Fixes the following error when fastset is enabled, caught by CI:
>>>>
>>>> [drm:ilk_validate_wm_level.part.8 [i915]] Sprite WM0 too large 56 (max 0)
>>>> [drm:ilk_validate_pipe_wm [i915]] LP0 watermark invalid
>>>> [drm:intel_crtc_atomic_check [i915]] No valid intermediate pipe watermarks are possible
>>>>
>>>> Triggered on debugfs_test.read_all_entries, but could have been any igt
>>>> test depending on ordering.
>>>>
>>>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
>>> So I'm no expert on this, but why is this not needed for g4x and vlv
>>> intermediate wm? I think the commit message should explain that. I think
>>> it should also explain why simply shutting the above warnings up is safe.
>>>
>>> I think once that's fixed I understand why we need this and why it works,
>>> but probably better to get an Ack from Ville to make sure.
>>> -Daniel
>> True, reason it's not needed there is because intermediate calculation can't fail.
>> And yeah best say because BIOS wm are bogus here.
> Ok, with that (maybe a bit more verbose) explained in the commit message:
>
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Hm, something fishy is going on. This should have been caught by sanitize_watermarks() early during boot. More investigation is needed...