[Intel-gfx] [PATCH] drm/i915/display: Fix shared dpll mismatch for bigjoiner slave

[Navare, Manasi]

Pushed to drm-intel-next, tahnks for the reviews.

Manasi

On Tue, Jul 20, 2021 at 12:53:23PM +0530, Nautiyal, Ankit K wrote:
> 
> On 7/20/2021 12:28 AM, Navare, Manasi wrote:
> >On Mon, Jul 19, 2021 at 11:47:51AM +0530, Nautiyal, Ankit K wrote:
> >>Patch looks good to me.
> >>
> >>Please find below some suggestions
> >>
> >>On 7/15/2021 4:04 AM, Manasi Navare wrote:
> >>>Currently when we do the HW state readout, we dont set the shared dpll to NULL
> >>>for the bigjoiner slave which should not have a DPLL assigned. So it has
> >>>some garbage while the HW state readout is NULL. So explicitly reset
> >>>the shared dpll for bigjoiner slave pipe.
> >>>
> >>>Bug: https://gitlab.freedesktop.org/drm/intel/-/issues/3465
> >>>Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> >>>Cc: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> >>>Tested-By: Swati Sharma <swati2.sharma at intel.com>
> >>checkpatch warning about tested-by tag.
> >>>Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> >>>---
> >>>  drivers/gpu/drm/i915/display/intel_display.c | 4 ++++
> >>>  1 file changed, 4 insertions(+)
> >>>
> >>>diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> >>>index 65ddb6ca16e6..c274bfb8e549 100644
> >>>--- a/drivers/gpu/drm/i915/display/intel_display.c
> >>>+++ b/drivers/gpu/drm/i915/display/intel_display.c
> >>>@@ -9006,6 +9006,10 @@ verify_crtc_state(struct intel_crtc *crtc,
> >>>  	if (!new_crtc_state->hw.active)
> >>>  		return;
> >>>+	if (new_crtc_state->bigjoiner_slave)
> >>>+		/* No PLLs set for slave */
> >>>+		pipe_config->shared_dpll = NULL;
> >>>+
> >>there is a check for bigjoiner_slave, couple of lines above this:
> >>
> >>if (new_crtc_state->bigjoiner_slave)
> >>                 master = new_crtc_state->bigjoiner_linked_crtc;
> >>
> >>Perhaps it will make sense to club the set shared_dpll to NULL, along with
> >>these lines.
> >Yup, thats where I was resetting in earlier patch but then it actually gets overridden in a function call
> >after this point so need to reset it after separately.
> >
> >Manasi
> 
> You are right. I missed that, pipe_config gets overwritten just before this
> point, so the change is at the right place.
> 
> Regards,
> 
> Ankit
> 
> 
> >
> >>In any case:
> >>
> >>Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> >>
> >>>  	intel_pipe_config_sanity_check(dev_priv, pipe_config);
> >>>  	if (!intel_pipe_config_compare(new_crtc_state,