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Patch "drm/tegra: dpaux: Fix transfers larger than 4 bytes" has been added to the 4.1-stable tree

PATCH [email protected] 1 participant 1 message Jul 30, 2015

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Stable branch DRM drivers Tegra architecture support DRM drivers for NVIDIA Tegra
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This is a note to let you know that I've just added the patch titled

drm/tegra: dpaux: Fix transfers larger than 4 bytes

to the 4.1-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-tegra-dpaux-fix-transfers-larger-than-4-bytes.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 3c1dae0a07c651526f8e878d223a88f82caa5a50 Mon Sep 17 00:00:00 2001

From: Thierry Reding <[email protected]>
Date: Thu, 11 Jun 2015 18:33:48 +0200
Subject: drm/tegra: dpaux: Fix transfers larger than 4 bytes

From: Thierry Reding <[email protected]>

commit 3c1dae0a07c651526f8e878d223a88f82caa5a50 upstream.

The DPAUX read/write FIFO registers aren't sequential in the register space, causing transfers larger than 4 bytes to cause accesses to non- existing FIFO registers.

Fixes 6b6b604215c6 ("drm/tegra: Add eDP support")
Signed-off-by Thierry Reding <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 drivers/gpu/drm/tegra/dpaux.c |   18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)
drivers/gpu/drm/tegra/dpaux.c +8 -10
@@ -72,34 +72,32 @@ static inline void tegra_dpaux_writel(st
 static void tegra_dpaux_write_fifo(struct tegra_dpaux *dpaux, const u8 *buffer,
 				   size_t size)
 {
-	unsigned long offset = DPAUX_DP_AUXDATA_WRITE(0);
 	size_t i, j;
 
-	for (i = 0; i < size; i += 4) {
-		size_t num = min_t(size_t, size - i, 4);
+	for (i = 0; i < DIV_ROUND_UP(size, 4); i++) {
+		size_t num = min_t(size_t, size - i * 4, 4);
 		unsigned long value = 0;
 
 		for (j = 0; j < num; j++)
-			value |= buffer[i + j] << (j * 8);
+			value |= buffer[i * 4 + j] << (j * 8);
 
-		tegra_dpaux_writel(dpaux, value, offset++);
+		tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXDATA_WRITE(i));
 	}
 }
 
 static void tegra_dpaux_read_fifo(struct tegra_dpaux *dpaux, u8 *buffer,
 				  size_t size)
 {
-	unsigned long offset = DPAUX_DP_AUXDATA_READ(0);
 	size_t i, j;
 
-	for (i = 0; i < size; i += 4) {
-		size_t num = min_t(size_t, size - i, 4);
+	for (i = 0; i < DIV_ROUND_UP(size, 4); i++) {
+		size_t num = min_t(size_t, size - i * 4, 4);
 		unsigned long value;
 
-		value = tegra_dpaux_readl(dpaux, offset++);
+		value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXDATA_READ(i));
 
 		for (j = 0; j < num; j++)
-			buffer[i + j] = value >> (j * 8);
+			buffer[i * 4 + j] = value >> (j * 8);
 	}
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.1/drm-tegra-dpaux-fix-transfers-larger-than-4-bytes.patch queue-4.1/drm-bridge-ptn3460-include-linux-gpio-consumer.h.patch