From: Brad Campbell Subject: Re: Radeon regression fix Date: Thu, 29 Sep 2011 23:21:02 +0800 Message-ID: <4E848CDE.1020707@fnarfbargle.com> References: <4E847ED4.5090703@fnarfbargle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Alex Deucher Cc: airlied@redhat.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org List-Id: dri-devel@lists.freedesktop.org On 29/09/11 22:36, Alex Deucher wrote: > On Thu, Sep 29, 2011 at 10:21 AM, Brad Campbell 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); > > Perhaps the delay is causing a problem. Does removing the udelay(400); help? How's this look ? diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c index 7ad43c6..aa5624a 100644 --- a/drivers/gpu/drm/radeon/atombios_dp.c +++ b/drivers/gpu/drm/radeon/atombios_dp.c @@ -128,12 +128,14 @@ static int radeon_dp_aux_native_write(struct radeon_connector *radeon_connector, while (1) { ret = radeon_process_aux_ch(dig_connector->dp_i2c_bus, msg, msg_bytes, NULL, 0, delay, &ack); + if (ret == 0 && ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)){ + udelay(400); + continue; + } if (ret < 0) return ret; if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_ACK) break; - else if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER) - udelay(400); else return -EIO; } @@ -158,14 +160,16 @@ static int radeon_dp_aux_native_read(struct radeon_connector *radeon_connector, while (1) { ret = radeon_process_aux_ch(dig_connector->dp_i2c_bus, msg, msg_bytes, recv, recv_bytes, delay, &ack); + if (ret == 0 && ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)){ + udelay(400); + continue; + } 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; }