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 <stable@xxxxxxxxxxxxxxx> know about it.
>From ae5c631e605a452a5a0e73205a92810c01ed954b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@xxxxxxxxxxxxxxx>
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 <ville.syrjala@xxxxxxxxxxxxxxx>
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 <djkurtz@xxxxxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Sean Paul <seanpaul@xxxxxxxxxxxx>
Fixes: 56f9eac05489 ("drm/i915/intel_i2c: use INDEX cycles for i2c read transactions")
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123194157.25367-2-ville.syrjala@xxxxxxxxxxxxxxx
Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
(cherry picked from commit c4deb62d7821672265b87952bcd1c808f3bf3e8f)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_i2c.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/gpu/drm/i915/intel_i2c.c
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -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 ville.syrjala@xxxxxxxxxxxxxxx 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