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Patch "drm/i915: Don't try indexed reads to alternate slave addresses" has been added to the 4.9-stable tree

PATCH [email protected] 1 participant 1 message Dec 4, 2017

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This is a note to let you know that I've just added the patch titled

drm/i915: Don't try indexed reads to alternate slave addresses

to the 4.9-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-i915-don-t-try-indexed-reads-to-alternate-slave-addresses.patch
and it can be found in the queue-4.9 subdirectory.

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

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From ae5c631e605a452a5a0e73205a92810c01ed954b Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <[email protected]>
Date: Thu, 23 Nov 2017 21:41:56 +0200
Subject: drm/i915: Don't try indexed reads to alternate slave addresses
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From: Ville Syrjälä <[email protected]>

commit ae5c631e605a452a5a0e73205a92810c01ed954b upstream.

We can only specify the one slave address to indexed reads/writes. Make sure the messages we check are destined to the same slave address before deciding to do an indexed transfer.

Cc Daniel Kurtz <[email protected]>
Cc Chris Wilson <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Sean Paul <[email protected]>
Fixes 56f9eac05489 ("drm/i915/intel_i2c: use INDEX cycles for i2c read transactions")
(cherry picked from commit c4deb62d7821672265b87952bcd1c808f3bf3e8f)
---
 drivers/gpu/drm/i915/intel_i2c.c |    1 +
 1 file changed, 1 insertion(+)
drivers/gpu/drm/i915/intel_i2c.c +1 -0
@@ -430,6 +430,7 @@ static bool
 gmbus_is_index_read(struct i2c_msg *msgs, int i, int num)
 {
 	return (i + 1 < num &&
+		msgs[i].addr == msgs[i + 1].addr &&
 		!(msgs[i].flags & I2C_M_RD) && msgs[i].len <= 2 &&
 		(msgs[i + 1].flags & I2C_M_RD));
 }

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

queue-4.9/drm-i915-prevent-zero-length-index-write.patch queue-4.9/drm-i915-don-t-try-indexed-reads-to-alternate-slave-addresses.patch