From ae5c631e605a452a5a0e73205a92810c01ed954b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Thu, 23 Nov 2017 21:41:56 +0200 Subject: [PATCH] drm/i915: Don't try indexed reads to alternate slave addresses MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: stable@vger.kernel.org Cc: Daniel Kurtz Cc: Chris Wilson Cc: Daniel Vetter Cc: Sean Paul Fixes: 56f9eac05489 ("drm/i915/intel_i2c: use INDEX cycles for i2c read transactions") Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20171123194157.25367-2-ville.syrjala@linux.intel.com Reviewed-by: Chris Wilson (cherry picked from commit c4deb62d7821672265b87952bcd1c808f3bf3e8f) Signed-off-by: Joonas Lahtinen --- drivers/gpu/drm/i915/intel_i2c.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c index eb5827110d8f..8affd47b98b8 100644 --- a/drivers/gpu/drm/i915/intel_i2c.c +++ b/drivers/gpu/drm/i915/intel_i2c.c @@ -438,6 +438,7 @@ 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)); }