From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Deucher Subject: [PATCH 1/3] drm/radeon/dp: handle zero sized i2c over aux transactions Date: Fri, 4 Apr 2014 10:40:56 -0400 Message-ID: <1396622458-2092-2-git-send-email-alexander.deucher@amd.com> References: <1396622458-2092-1-git-send-email-alexander.deucher@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-qc0-f177.google.com (mail-qc0-f177.google.com [209.85.216.177]) by gabe.freedesktop.org (Postfix) with ESMTP id 057376EDA0 for ; Fri, 4 Apr 2014 07:41:06 -0700 (PDT) Received: by mail-qc0-f177.google.com with SMTP id w7so3501198qcr.8 for ; Fri, 04 Apr 2014 07:41:05 -0700 (PDT) In-Reply-To: <1396622458-2092-1-git-send-email-alexander.deucher@amd.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: dri-devel@lists.freedesktop.org, jani.nikula@linux.intel.com Cc: Alex Deucher List-Id: dri-devel@lists.freedesktop.org Needed for proper i2c over aux handling for certain monitors and configurations (e.g., dp bridges or adapters). Signed-off-by: Alex Deucher --- drivers/gpu/drm/radeon/atombios_dp.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c index 8b0ab17..e914008 100644 --- a/drivers/gpu/drm/radeon/atombios_dp.c +++ b/drivers/gpu/drm/radeon/atombios_dp.c @@ -143,6 +143,7 @@ static int radeon_process_aux_ch(struct radeon_i2c_chan *chan, } #define HEADER_SIZE 4 +#define BARE_ADDRESS_SIZE 3 static ssize_t radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) @@ -160,13 +161,16 @@ radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) tx_buf[0] = msg->address & 0xff; tx_buf[1] = msg->address >> 8; tx_buf[2] = msg->request << 4; - tx_buf[3] = msg->size - 1; + tx_buf[3] = msg->size ? (msg->size - 1) : 0; switch (msg->request & ~DP_AUX_I2C_MOT) { case DP_AUX_NATIVE_WRITE: case DP_AUX_I2C_WRITE: tx_size = HEADER_SIZE + msg->size; - tx_buf[3] |= tx_size << 4; + if (msg->size == 0) + tx_buf[3] |= BARE_ADDRESS_SIZE << 4; + else + tx_buf[3] |= tx_size << 4; memcpy(tx_buf + HEADER_SIZE, msg->buffer, msg->size); ret = radeon_process_aux_ch(chan, tx_buf, tx_size, NULL, 0, delay, &ack); @@ -177,7 +181,10 @@ radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) case DP_AUX_NATIVE_READ: case DP_AUX_I2C_READ: tx_size = HEADER_SIZE; - tx_buf[3] |= tx_size << 4; + if (msg->size == 0) + tx_buf[3] |= BARE_ADDRESS_SIZE << 4; + else + tx_buf[3] |= tx_size << 4; ret = radeon_process_aux_ch(chan, tx_buf, tx_size, msg->buffer, msg->size, delay, &ack); break; @@ -186,7 +193,7 @@ radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) break; } - if (ret > 0) + if (ret >= 0) msg->reply = ack >> 4; return ret; -- 1.8.3.1