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Commit b858baba authored by Ville Syrjälä's avatar Ville Syrjälä Committed by Greg Kroah-Hartman
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drm/i915: Don't try indexed reads to alternate slave addresses 



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@chromium.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <seanpaul@chromium.org>
Fixes: 56f9eac0 ("drm/i915/intel_i2c: use INDEX cycles for i2c read transactions")
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123194157.25367-2-ville.syrjala@linux.intel.com


Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
(cherry picked from commit c4deb62d7821672265b87952bcd1c808f3bf3e8f)
Signed-off-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9ea40d14

drivers/gpu/drm/i915/intel_i2c.c

+1 −0
Original line number Diff line number Diff line
@@ -394,6 +394,7 @@ 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));

}