Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1511693

[PATCH 4.4 13/51] drm/i915/gen9: fix the WaWmMemoryReadLatency implementation

From Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups linux.kernel
Subject [PATCH 4.4 13/51] drm/i915/gen9: fix the WaWmMemoryReadLatency implementation
Date 2016-10-29 16:00 +0200
Message-ID <sxCkY-6TH-93@gated-at.bofh.it> (permalink)
References <sxCkW-6TH-31@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Paulo Zanoni <paulo.r.zanoni@intel.com>

commit 4e4d3814a9bb4d71cd3ff0701d8d7041edefd8f0 upstream.

Bspec says:
  "The mailbox response data may not account for memory read latency.
   If the mailbox response data for level 0 is 0us, add 2 microseconds
   to the result for each valid level."

This means we should only do the +2 in case wm[0] == 0, not always.

So split the sanitizing implementation from the WA implementation and
fix the WA implementation.

v2: Add Fixes tag (Maarten).

Fixes: 367294be7c25 ("drm/i915/gen9: Add 2us read latency to WM level")
Cc: Vandana Kannan <vandana.kannan@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1474578035-424-5-git-send-email-paulo.r.zanoni@intel.com
(cherry picked from commit 0727e40a48a1d08cf54ce2c01e120864b92e59bf)
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 |   42 ++++++++++++++++++++--------------------
 1 file changed, 22 insertions(+), 20 deletions(-)

--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2097,32 +2097,34 @@ static void intel_read_wm_latency(struct
 				GEN9_MEM_LATENCY_LEVEL_MASK;
 
 		/*
+		 * If a level n (n > 1) has a 0us latency, all levels m (m >= n)
+		 * need to be disabled. We make sure to sanitize the values out
+		 * of the punit to satisfy this requirement.
+		 */
+		for (level = 1; level <= max_level; level++) {
+			if (wm[level] == 0) {
+				for (i = level + 1; i <= max_level; i++)
+					wm[i] = 0;
+				break;
+			}
+		}
+
+		/*
 		 * WaWmMemoryReadLatency:skl
 		 *
 		 * punit doesn't take into account the read latency so we need
-		 * to add 2us to the various latency levels we retrieve from
-		 * the punit.
-		 *   - W0 is a bit special in that it's the only level that
-		 *   can't be disabled if we want to have display working, so
-		 *   we always add 2us there.
-		 *   - For levels >=1, punit returns 0us latency when they are
-		 *   disabled, so we respect that and don't add 2us then
-		 *
-		 * Additionally, if a level n (n > 1) has a 0us latency, all
-		 * levels m (m >= n) need to be disabled. We make sure to
-		 * sanitize the values out of the punit to satisfy this
-		 * requirement.
+		 * to add 2us to the various latency levels we retrieve from the
+		 * punit when level 0 response data us 0us.
 		 */
-		wm[0] += 2;
-		for (level = 1; level <= max_level; level++)
-			if (wm[level] != 0)
+		if (wm[0] == 0) {
+			wm[0] += 2;
+			for (level = 1; level <= max_level; level++) {
+				if (wm[level] == 0)
+					break;
 				wm[level] += 2;
-			else {
-				for (i = level + 1; i <= max_level; i++)
-					wm[i] = 0;
-
-				break;
 			}
+		}
+
 	} else if (IS_HASWELL(dev) || IS_BROADWELL(dev)) {
 		uint64_t sskpd = I915_READ64(MCH_SSKPD);
 

Back to linux.kernel | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

[PATCH 4.4 00/51] 4.4.29-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:00 +0200
  [PATCH 4.4 23/51] powerpc/eeh: Null check uses of eeh_pe_bus_get Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:00 +0200
  [PATCH 4.4 36/51] ASoC: dapm: Fix kcontrol creation for output driver widget Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:00 +0200
  [PATCH 4.4 28/51] spi: spi-fsl-dspi: Drop extra spi_master_put in device remove function Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:00 +0200
  [PATCH 4.4 29/51] mwifiex: correct aid value during tdls setup Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:00 +0200
  [PATCH 4.4 16/51] drm/i915: Unalias obj->phys_handle and obj->userptr Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:00 +0200
  [PATCH 4.4 13/51] drm/i915/gen9: fix the WaWmMemoryReadLatency implementation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:00 +0200
  [PATCH 4.4 20/51] ipip: Properly mark ipip GRO packets as encapsulated. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:00 +0200
  [PATCH 4.4 06/51] drm/amdgpu/dce11: add missing drm_mode_config_cleanup call Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:00 +0200
  [PATCH 4.4 46/51] perf hists browser: Fix event group display Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:00 +0200
  [PATCH 4.4 03/51] drm/amdgpu/dce10: disable hpd on local panels Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:00 +0200
  [PATCH 4.4 41/51] s390/cio: fix accidental interrupt enabling during resume Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:00 +0200
  [PATCH 4.4 50/51] powerpc/nvram: Fix an incorrect partition merge Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 34/51] ASoC: dapm: Fix possible uninitialized variable in snd_soc_dapm_get_volsw() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 45/51] clk: divider: Fix clk_divider_round_rate() to use clk_readl() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 47/51] perf symbols: Check symbol_conf.allow_aliases for kallsyms loading too Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 10/51] drm/radeon: change vblank_times calculation method to reduce computational error. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 21/51] tunnels: Dont apply GRO to multiple layers of encapsulation. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 04/51] drm/amdgpu/dce8: disable hpd on local panels Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 17/51] mm/hugetlb: fix memory offline with hugepage size > memory block size Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 25/51] genirq/generic_chip: Add irq_unmap callback Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 02/51] drm/amdgpu: fix IB alignment for UVD Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 14/51] Revert "drm/i915: Check live status before reading edid" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 42/51] s390/con3270: fix use of uninitialised data Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 05/51] drm/amdgpu/dce11: disable hpd on local panels Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 51/51] ARM: pxa: pxa_cplds: fix interrupt handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 44/51] clk: qoriq: fix a register offset error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 26/51] uio: fix dmem_region_start computation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 32/51] hwrng: omap - Only fail if pm_runtime_get_sync returns < 0 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 31/51] crypto: arm/ghash-ce - add missing async import/export Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 40/51] x86/mm: Expand the exception table logic to allow new handling options Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 33/51] ASoC: topology: Fix error return code in soc_tplg_dapm_widget_create() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 22/51] tunnels: Remove encapsulation offloads on decap. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 08/51] drm/radeon: narrow asic_init for virtualization Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 37/51] staging: r8188eu: Fix scheduling while atomic splat Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 07/51] drm/amdgpu: change vblank_times calculation method to reduce computational error. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 19/51] posix_acl: Clear SGID bit when setting file permissions Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 09/51] drm/radeon/si/dpm: fix phase shedding setup Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 35/51] ASoC: dapm: Fix value setting for _ENUM_DOUBLE MUXs second channel Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 11/51] drm/vmwgfx: Limit the user-space command buffer size Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 43/51] s390/con3270: fix insufficient space padding Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 49/51] mpt3sas: Dont spam logs if logging level is 0 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 38/51] power: bq24257: Fix use of uninitialized pointer bq->charger Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  [PATCH 4.4 18/51] brcmfmac: avoid potential stack overflow in brcmf_cfg80211_start_ap() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-29 16:30 +0200
  Re: [PATCH 4.4 00/51] 4.4.29-stable review Shuah Khan <shuah.kh@samsung.com> - 2016-10-30 01:10 +0200
  Re: [PATCH 4.4 00/51] 4.4.29-stable review Guenter Roeck <linux@roeck-us.net> - 2016-10-30 02:50 +0200

csiph-web