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


Groups > linux.kernel > #1214850

[PATCH 3.19.y-ckt 101/130] drm/i915: Replace WARN inside I915_READ64_2x32 with retry loop

Path csiph.com!eternal-september.org!feeder.eternal-september.org!aioe.org!bofh.it!news.nic.it!robomod
From Kamal Mostafa <kamal@canonical.com>
Newsgroups linux.kernel
Subject [PATCH 3.19.y-ckt 101/130] drm/i915: Replace WARN inside I915_READ64_2x32 with retry loop
Date Fri, 28 Aug 2015 00:20:02 +0200
Message-ID <q2dGy-Mo-25@gated-at.bofh.it> (permalink)
References <q2dGx-Mo-3@gated-at.bofh.it>
X-Original-To linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com
X-Mailer git-send-email 1.9.1
MIME-Version 1.0
Content-Type text/plain; charset=UTF-8
Content-Transfer-Encoding 8bit
X-Extended-Stable 3.19
Sender robomod@news.nic.it
List-ID <linux-kernel.vger.kernel.org>
X-Mailing-List linux-kernel@vger.kernel.org
Approved robomod@news.nic.it
Lines 56
Organization linux.* mail to news gateway
X-Original-Cc Chris Wilson <chris@chris-wilson.co.uk>, Michał Winiarski <michal.winiarski@intel.com>, Daniel Vetter <daniel.vetter@ffwll.ch>, Kamal Mostafa <kamal@canonical.com>
X-Original-Date Thu, 27 Aug 2015 15:11:32 -0700
X-Original-Message-ID <1440713521-5906-102-git-send-email-kamal@canonical.com>
X-Original-References <1440713521-5906-1-git-send-email-kamal@canonical.com>
X-Original-Sender linux-kernel-owner@vger.kernel.org
Xref csiph.com linux.kernel:1214850

Show key headers only | View raw


3.19.8-ckt6 -stable review patch.  If anyone has any objections, please let me know.

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

From: Chris Wilson <chris@chris-wilson.co.uk>

commit ee0a227b7ac6e75f28e10269f81c7ec6eb600952 upstream.

Since we may conceivably encounter situations where the upper part of the
64bit register changes between reads, for example when a timestamp
counter overflows, change the WARN into a retry loop.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 drivers/gpu/drm/i915/i915_drv.h | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 44a3c38..46ef49b 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2996,15 +2996,14 @@ int vlv_freq_opcode(struct drm_i915_private *dev_priv, int val);
 #define I915_READ64(reg)	dev_priv->uncore.funcs.mmio_readq(dev_priv, (reg), true)
 
 #define I915_READ64_2x32(lower_reg, upper_reg) ({			\
-		u32 upper = I915_READ(upper_reg);			\
-		u32 lower = I915_READ(lower_reg);			\
-		u32 tmp = I915_READ(upper_reg);				\
-		if (upper != tmp) {					\
-			upper = tmp;					\
-			lower = I915_READ(lower_reg);			\
-			WARN_ON(I915_READ(upper_reg) != upper);		\
-		}							\
-		(u64)upper << 32 | lower; })
+	u32 upper, lower, tmp;						\
+	tmp = I915_READ(upper_reg);					\
+	do {								\
+		upper = tmp;						\
+		lower = I915_READ(lower_reg);				\
+		tmp = I915_READ(upper_reg);				\
+	} while (upper != tmp);						\
+	(u64)upper << 32 | lower; })
 
 #define POSTING_READ(reg)	(void)I915_READ_NOTRACE(reg)
 #define POSTING_READ16(reg)	(void)I915_READ16_NOTRACE(reg)
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

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


Thread

[PATCH 3.19.y-ckt 101/130] drm/i915: Replace WARN inside I915_READ64_2x32 with retry loop Kamal Mostafa <kamal@canonical.com> - 2015-08-28 00:20 +0200

csiph-web