diff options
| author |   Ville Syrjälä <ville.syrjala@linux.intel.com> | 2017-11-23 21:41:57 +0200 |
|---|---|---|
| committer | Ville Syrjälä <ville.syrjala@linux.intel.com> | 2017-11-24 16:41:30 +0200 |
| commit | bb9e0d4bca50f429152e74a459160b41f3d60fb2 (patch) | |
| tree | be506f0168699c08f2757a812de6789e3582f14e | |
| parent | drm/i915: Don't try indexed reads to alternate slave addresses (diff) | |
| download | linux-dev-bb9e0d4bca50f429152e74a459160b41f3d60fb2.tar.xz linux-dev-bb9e0d4bca50f429152e74a459160b41f3d60fb2.zip | |
drm/i915: Prevent zero length "index" write
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: stable@vger.kernel.org
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: 56f9eac05489 ("drm/i915/intel_i2c: use INDEX cycles for i2c read transactions")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171123194157.25367-3-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
| -rw-r--r-- | drivers/gpu/drm/i915/intel_i2c.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c index 8affd47b98b8..49fdf09f9919 100644 --- a/drivers/gpu/drm/i915/intel_i2c.c +++ b/drivers/gpu/drm/i915/intel_i2c.c @@ -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)); } |