3.16.55-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Ville Syrjälä <[email protected]> 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 <[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") Signed-off-by: Ville Syrjälä <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected] Reviewed-by: Chris Wilson <[email protected]> (cherry picked from commit bb9e0d4bca50f429152e74a459160b41f3d60fb2) Signed-off-by: Joonas Lahtinen <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> --- drivers/gpu/drm/i915/intel_i2c.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/gpu/drm/i915/intel_i2c.c +++ b/drivers/gpu/drm/i915/intel_i2c.c @@ -449,7 +449,8 @@ gmbus_is_index_read(struct i2c_msg *msgs { 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)); }
