On 29/09/11 22:36, Alex Deucher wrote:
On Thu, Sep 29, 2011 at 10:21 AM, Brad Campbellbrad@fnarfbargle.com wrote:
This patch fixes a regression introduced between 2.6.39& 3.1-rc1 whereby the displayport AUX channel stopped re-trying commands that elicited a DEFER response.
It should still be retrying, just restructured slightly. The retry logic just moved into radeon_dp_i2c_aux_ch(), radeon_dp_aux_native_write(), and radeon_dp_aux_native_read(), e.g.,
else if ((ack& AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER) udelay(400);
One problem with that logic I'm afraid.
if (ret == 0) return -EPROTO; if (ret < 0) return ret; if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_ACK) return ret; else if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER) udelay(400); else return -EIO; }
ret == 0 with a defer as there is no data in the packet. It never even gets past the first hurdle.