Hi Stephen,

On Tue, Nov 30, 2021 at 10:33:53AM +1100, Stephen Rothwell wrote:

Hi all,

Today's linux-next merge of the drm tree got a conflict in:

  drivers/gpu/drm/vc4/vc4_kms.c

between commits:

  f927767978d2 ("drm/vc4: kms: Fix return code check")
  d354699e2292 ("drm/vc4: kms: Don't duplicate pending commit")

from the drm-misc-fixes tree and commit:

  16e101051f32 ("drm/vc4: Increase the core clock based on HVS load")

from the drm tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

Unfortunately the merge resolution isn't entirely correct :/

There's multiple conflicts between those two branches on that file, but
things went wrong between 16e101051f32 and 0c980a006d3f

The first one changes the logic a bit for the clk_set_min_rate argument,
and the second moves the clk_set_min_rate around.

However, the merge resolution reintroduced the initial clk_set_min_rate
call line (line 373), without changing the logic of the proper call site
(line 396).

This is the patch to fix the resolution:

-- >8 --

--- a/drivers/gpu/drm/vc4/vc4_kms.c	2021-11-30 08:56:28.748524275 +0100
+++ b/drivers/gpu/drm/vc4/vc4_kms.c	2021-11-29 15:46:11.692151678 +0100

@@ -365,14 +365,6 @@
 		vc4_hvs_mask_underrun(dev, vc4_crtc_state->assigned_channel);
 	}

-	if (vc4->hvs->hvs5) {
-		unsigned long core_rate = max_t(unsigned long,
-						500000000,
-						new_hvs_state->core_clock_rate);
-
-		clk_set_min_rate(hvs->core_clk, core_rate);
-	}
-
 	for (channel = 0; channel < HVS_NUM_CHANNELS; channel++) {
 		struct drm_crtc_commit *commit;
 		int ret;

@@ -392,8 +384,13 @@
 		old_hvs_state->fifo_state[channel].pending_commit = NULL;
 	}

-	if (vc4->hvs->hvs5)
-		clk_set_min_rate(hvs->core_clk, 500000000);
+	if (vc4->hvs->hvs5) {
+		unsigned long core_rate = max_t(unsigned long,
+						500000000,
+						new_hvs_state->core_clock_rate);
+
+		clk_set_min_rate(hvs->core_clk, core_rate);
+	}

 	drm_atomic_helper_commit_modeset_disables(dev, state);
-- >8 --

I'm wondering though, do you have access to the drm-rerere tree? I've
fixed up the merge yesterday to deal with this conflict and the conflict
resolution should be stored there already.

Maxime