From: Ville Syrjälä Date: Thu, 23 Nov 2017 19:41:56 +0000 (+0200) Subject: drm/i915: Don't try indexed reads to alternate slave addresses X-Git-Tag: v3.18.86~2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b858baba6773bfdfbd3fd419a3dfa4eacdc6f107;p=thirdparty%2Fkernel%2Fstable.git drm/i915: Don't try indexed reads to alternate slave addresses 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 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c index ae628001fd978..6f3b747eeda5f 100644 --- a/drivers/gpu/drm/i915/intel_i2c.c +++ b/drivers/gpu/drm/i915/intel_i2c.c @@ -394,6 +394,7 @@ 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)); }