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authorVille Syrjälä <ville.syrjala@linux.intel.com>2016-04-20 16:43:56 +0300
committerJani Nikula <jani.nikula@intel.com>2016-04-27 10:57:00 +0300
commit4ea3959018d09edfa36a9e7b5ccdbd4ec4b99e49 (patch)
tree23d528425c25122d9935d2ead7f8ded64dc6e1d9
parent60b3143c7cac7e8d2ca65c0b347466c5776395d1 (diff)
drm/i915: Make RPS EI/thresholds multiple of 25 on SNB-BDWdrm-intel-fixes-2016-05-02
Somehow my SNB GT1 (Dell XPS 8300) gets very unhappy around GPU hangs if the RPS EI/thresholds aren't suitably aligned. It seems like scheduling/timer interupts stop working somehow and things get stuck eg. in usleep_range(). I bisected the problem down to commit 8a5864377b12 ("drm/i915/skl: Restructured the gen6_set_rps_thresholds function") I observed that before all the values were at least multiples of 25, but afterwards they are not. And rounding things up to the next multiple of 25 does seem to help, so lets' do that. I also tried roundup(..., 5) but that wasn't sufficient. Also I have no idea if we might need this sort of thing on gen9+ as well. These are the original EI/thresholds: LOW_POWER GEN6_RP_UP_EI 12500 GEN6_RP_UP_THRESHOLD 11800 GEN6_RP_DOWN_EI 25000 GEN6_RP_DOWN_THRESHOLD 21250 BETWEEN GEN6_RP_UP_EI 10250 GEN6_RP_UP_THRESHOLD 9225 GEN6_RP_DOWN_EI 25000 GEN6_RP_DOWN_THRESHOLD 18750 HIGH_POWER GEN6_RP_UP_EI 8000 GEN6_RP_UP_THRESHOLD 6800 GEN6_RP_DOWN_EI 25000 GEN6_RP_DOWN_THRESHOLD 15000 These are after 8a5864377b12: LOW_POWER GEN6_RP_UP_EI 12500 GEN6_RP_UP_THRESHOLD 11875 GEN6_RP_DOWN_EI 25000 GEN6_RP_DOWN_THRESHOLD 21250 BETWEEN GEN6_RP_UP_EI 10156 GEN6_RP_UP_THRESHOLD 9140 GEN6_RP_DOWN_EI 25000 GEN6_RP_DOWN_THRESHOLD 18750 HIGH_POWER GEN6_RP_UP_EI 7812 GEN6_RP_UP_THRESHOLD 6640 GEN6_RP_DOWN_EI 25000 GEN6_RP_DOWN_THRESHOLD 15000 And these are what we have after this patch: LOW_POWER GEN6_RP_UP_EI 12500 GEN6_RP_UP_THRESHOLD 11875 GEN6_RP_DOWN_EI 25000 GEN6_RP_DOWN_THRESHOLD 21250 BETWEEN GEN6_RP_UP_EI 10175 GEN6_RP_UP_THRESHOLD 9150 GEN6_RP_DOWN_EI 25000 GEN6_RP_DOWN_THRESHOLD 18750 HIGH_POWER GEN6_RP_UP_EI 7825 GEN6_RP_UP_THRESHOLD 6650 GEN6_RP_DOWN_EI 25000 GEN6_RP_DOWN_THRESHOLD 15000 Cc: stable@vger.kernel.org Cc: Akash Goel <akash.goel@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Testcase: igt/kms_pipe_crc_basic/hang-read-crc-pipe-B Fixes: 8a5864377b12 ("drm/i915/skl: Restructured the gen6_set_rps_thresholds function") Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1461159836-9108-1-git-send-email-ville.syrjala@linux.intel.com Acked-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com> (cherry picked from commit 8a292d016d1cc4938ff14b4df25328230b08a408) Signed-off-by: Jani Nikula <jani.nikula@intel.com>
-rw-r--r--drivers/gpu/drm/i915/i915_reg.h9
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index f76cbf3e5d1e..fffdac801d3b 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2907,7 +2907,14 @@ enum skl_disp_power_wells {
#define GEN6_RP_STATE_CAP _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5998)
#define BXT_RP_STATE_CAP _MMIO(0x138170)
-#define INTERVAL_1_28_US(us) (((us) * 100) >> 7)
+/*
+ * Make these a multiple of magic 25 to avoid SNB (eg. Dell XPS
+ * 8300) freezing up around GPU hangs. Looks as if even
+ * scheduling/timer interrupts start misbehaving if the RPS
+ * EI/thresholds are "bad", leading to a very sluggish or even
+ * frozen machine.
+ */
+#define INTERVAL_1_28_US(us) roundup(((us) * 100) >> 7, 25)
#define INTERVAL_1_33_US(us) (((us) * 3) >> 2)
#define INTERVAL_0_833_US(us) (((us) * 6) / 5)
#define GT_INTERVAL_FROM_US(dev_priv, us) (IS_GEN9(dev_priv) ? \

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