| From | Ben Hutchings <> | Date | Wed, 28 Feb 2018 15:20:18 +0000 | Subject | [PATCH 3.16 018/254] drm/i915: Don't try indexed reads to alternate slave addresses |
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3.16.55-rc1 review patch. If anyone has any objections, please let me know.
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From: Ville Syrjälä <ville.syrjala@linux.intel.com>
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: 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/20171123194157.25367-2-ville.syrjala@linux.intel.com Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (cherry picked from commit c4deb62d7821672265b87952bcd1c808f3bf3e8f) Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- 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 @@ -448,6 +448,7 @@ 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)); }
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