Patch "drm/i915/gen9: Increase PCODE request timeout to 50ms" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    drm/i915/gen9: Increase PCODE request timeout to 50ms

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-i915-gen9-increase-pcode-request-timeout-to-50ms.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From d253371c4c2f5fc2d884ef25f64decd7549aff5a Mon Sep 17 00:00:00 2001
From: Imre Deak <imre.deak@intel.com>
Date: Fri, 24 Feb 2017 16:32:10 +0200
Subject: drm/i915/gen9: Increase PCODE request timeout to 50ms
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From: Imre Deak <imre.deak@intel.com>

commit d253371c4c2f5fc2d884ef25f64decd7549aff5a upstream.

After
commit 2c7d0602c815277f7cb7c932b091288710d8aba7
Author: Imre Deak <imre.deak@intel.com>
Date:   Mon Dec 5 18:27:37 2016 +0200

    drm/i915/gen9: Fix PCODE polling during CDCLK change notification

there is still one report of the CDCLK-change request timing out on a
KBL machine, see the Reference link. On that machine the maximum time
the request took to succeed was 34ms, so increase the timeout to 50ms.

v2:
- Change timeout from 100 to 50 ms to maintain the current 50 ms limit
  for atomic waits in the driver. (Chris, Tvrtko)

Reference: https://bugs.freedesktop.org/show_bug.cgi?id=99345
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1487946730-17162-1-git-send-email-imre.deak@intel.com
(cherry picked from commit 0129936ddda26afd5d9d207c4e86b2425952579f)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/i915/intel_pm.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -7960,10 +7960,10 @@ static bool skl_pcode_try_request(struct
  * @timeout_base_ms: timeout for polling with preemption enabled
  *
  * Keep resending the @request to @mbox until PCODE acknowledges it, PCODE
- * reports an error or an overall timeout of @timeout_base_ms+10 ms expires.
+ * reports an error or an overall timeout of @timeout_base_ms+50 ms expires.
  * The request is acknowledged once the PCODE reply dword equals @reply after
  * applying @reply_mask. Polling is first attempted with preemption enabled
- * for @timeout_base_ms and if this times out for another 10 ms with
+ * for @timeout_base_ms and if this times out for another 50 ms with
  * preemption disabled.
  *
  * Returns 0 on success, %-ETIMEDOUT in case of a timeout, <0 in case of some
@@ -7999,14 +7999,15 @@ int skl_pcode_request(struct drm_i915_pr
 	 * worst case) _and_ PCODE was busy for some reason even after a
 	 * (queued) request and @timeout_base_ms delay. As a workaround retry
 	 * the poll with preemption disabled to maximize the number of
-	 * requests. Increase the timeout from @timeout_base_ms to 10ms to
+	 * requests. Increase the timeout from @timeout_base_ms to 50ms to
 	 * account for interrupts that could reduce the number of these
-	 * requests.
+	 * requests, and for any quirks of the PCODE firmware that delays
+	 * the request completion.
 	 */
 	DRM_DEBUG_KMS("PCODE timeout, retrying with preemption disabled\n");
 	WARN_ON_ONCE(timeout_base_ms > 3);
 	preempt_disable();
-	ret = wait_for_atomic(COND, 10);
+	ret = wait_for_atomic(COND, 50);
 	preempt_enable();
 
 out:


Patches currently in stable-queue which might be from imre.deak@intel.com are

queue-4.9/drm-i915-gen9-increase-pcode-request-timeout-to-50ms.patch