[0683/1094] Revert "drm/i915: fix infinite loop at gen6_update_ring_freq"

Commit Message

Dheeraj Jamwal Oct. 21, 2014, 10:54 a.m. UTC

From: Daniel Vetter <[e-mail]>

This reverts commit 4b28a1f3ef55a3b0b68dbab1fe6dbaf18e186710.

This patch duct-tapes over some issue in the current bdw rps patches
which must wait with enabling rc6/rps until the very first batch has
been submitted by userspace.

But those patches aren't merged yet, and for upstream we need to have
an in-kernel emission of the very first batch. I shouldn't have
merged this patch so let's revert it again.

Also Imre noticed that even when rps is set up normally there's a
small window (due to the 1s delay of the async rps init work) where we
could runtime suspend already and blow up all over the place. Imre has
a proper fix to block runtime pm until the rps init work has
successfully completed.

Cc: Paulo Zanoni <[e-mail]>
Cc: Imre Deak <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>
(cherry picked from commit fc1744ff7ba63cabf858c55217382104e9dd94ed)

Signed-off-by: Dheeraj Jamwal <[e-mail]>
---
 drivers/gpu/drm/i915/intel_pm.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Patch

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 69c9dec..4d1890f 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3564,8 +3564,7 @@  void gen6_update_ring_freq(struct drm_device *dev)
 	 * to use for memory access.  We do this by specifying the IA frequency
 	 * the PCU should use as a reference to determine the ring frequency.
 	 */
-	for (gpu_freq = dev_priv->rps.max_freq_softlimit;
-	     gpu_freq >= dev_priv->rps.min_freq_softlimit && gpu_freq != 0;
+	for (gpu_freq = dev_priv->rps.max_freq_softlimit; gpu_freq >= dev_priv->rps.min_freq_softlimit;
 	     gpu_freq--) {
 		int diff = dev_priv->rps.max_freq_softlimit - gpu_freq;
 		unsigned int ia_freq = 0, ring_freq = 0;