Commit 88e1bb2a authored by Ville Syrjälä's avatar Ville Syrjälä Committed by Greg Kroah-Hartman

drm/i915: Prevent zero length "index" write

commit 56350fb8978bbf4aafe08f21234e161dd128b417 upstream.

The hardware always writes one or two bytes in the index portion of
an indexed transfer. Make sure the message we send as the index
doesn't have a zero length.

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: 's avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123194157.25367-3-ville.syrjala@linux.intel.comReviewed-by: 's avatarChris Wilson <chris@chris-wilson.co.uk>
(cherry picked from commit bb9e0d4bca50f429152e74a459160b41f3d60fb2)
Signed-off-by: 's avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: 's avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e522b924
......@@ -439,7 +439,8 @@ 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].flags & I2C_M_RD) &&
(msgs[i].len == 1 || msgs[i].len == 2) &&
(msgs[i + 1].flags & I2C_M_RD));
}
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment