From 0bbca274a31c2366414d8d3f95e03d1c4674d93f Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Mon, 7 Mar 2016 17:56:57 +0200 Subject: [PATCH] drm/i915: Actually retry with bit-banging after GMBUS timeout MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit After the GMBUS transfer times out, we set force_bit=1 and return -EAGAIN expecting the i2c core to call the .master_xfer hook again so that we will retry the same transfer via bit-banging. This is in case the gmbus hardware is somehow faulty. Unfortunately we left adapter->retries to 0, meaning the i2c core didn't actually do the retry. Let's tell the core we want one retry when we return -EAGAIN. Note that i2c-algo-bit also uses this retry count for some internal retries, so we'll end up increasing those a bit as well. Cc: Jani Nikula Cc: drm-intel-fixes@lists.freedesktop.org Fixes: bffce907d640 ("drm/i915: abstract i2c bit banging fallback in gmbus xfer") Signed-off-by: Ville Syrjälä Link: http://patchwork.freedesktop.org/patch/msgid/1457366220-29409-2-git-send-email-ville.syrjala@linux.intel.com Reviewed-by: Jani Nikula (cherry picked from commit 8b1f165a4a8f64c28cf42d10e1f4d3b451dedc51) Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/intel_i2c.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c index deb8282c26d8..52fbe530fc9e 100644 --- a/drivers/gpu/drm/i915/intel_i2c.c +++ b/drivers/gpu/drm/i915/intel_i2c.c @@ -664,6 +664,12 @@ int intel_setup_gmbus(struct drm_device *dev) bus->adapter.algo = &gmbus_algorithm; + /* + * We wish to retry with bit banging + * after a timed out GMBUS attempt. + */ + bus->adapter.retries = 1; + /* By default use a conservative clock rate */ bus->reg0 = pin | GMBUS_RATE_100KHZ; -- 2.20.1