diff mbox series

[1/3] drm/dp: extract drm_dp_dpcd_poll_act_handled()

Message ID 3d91f7b6639960fe688eb6ae0236254adae3e82d.1731942780.git.jani.nikula@intel.com (mailing list archive)
State New
Headers show
Series drm/dp: extract payload helpers | expand

Commit Message

Jani Nikula Nov. 18, 2024, 3:14 p.m. UTC
SST with 128b/132b channel coding needs this too. Extract to a separate
helper, independent of MST.

Pass timeout in as a parameter, anticipating that we can reduce the
timeout for SST.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c       | 54 ++++++++++++++++++-
 drivers/gpu/drm/display/drm_dp_mst_topology.c | 36 +------------
 include/drm/display/drm_dp_helper.h           |  2 +
 3 files changed, 57 insertions(+), 35 deletions(-)

Comments

Imre Deak Nov. 20, 2024, 2:59 p.m. UTC | #1
On Mon, Nov 18, 2024 at 05:14:52PM +0200, Jani Nikula wrote:
> SST with 128b/132b channel coding needs this too. Extract to a separate
> helper, independent of MST.
> 
> Pass timeout in as a parameter, anticipating that we can reduce the
> timeout for SST.

I wish there was a DP Standard section making the above clear,
but I suppose we just deduct that except of the side-band messaging,
every other payload programming and ACT signaling is required for
128b/132b SST.

> 

Cc: Lyude Paul <lyude@redhat.com>

> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
>  drivers/gpu/drm/display/drm_dp_helper.c       | 54 ++++++++++++++++++-
>  drivers/gpu/drm/display/drm_dp_mst_topology.c | 36 +------------
>  include/drm/display/drm_dp_helper.h           |  2 +
>  3 files changed, 57 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
> index 6ee51003de3c..b7e03bf02cd8 100644
> --- a/drivers/gpu/drm/display/drm_dp_helper.c
> +++ b/drivers/gpu/drm/display/drm_dp_helper.c
> @@ -22,15 +22,16 @@
>  
>  #include <linux/backlight.h>
>  #include <linux/delay.h>
> +#include <linux/dynamic_debug.h>
>  #include <linux/errno.h>
>  #include <linux/i2c.h>
>  #include <linux/init.h>
> +#include <linux/iopoll.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/sched.h>
>  #include <linux/seq_file.h>
>  #include <linux/string_helpers.h>
> -#include <linux/dynamic_debug.h>
>  
>  #include <drm/display/drm_dp_helper.h>
>  #include <drm/display/drm_dp_mst_helper.h>
> @@ -779,6 +780,57 @@ int drm_dp_dpcd_read_phy_link_status(struct drm_dp_aux *aux,
>  }
>  EXPORT_SYMBOL(drm_dp_dpcd_read_phy_link_status);
>  
> +static int read_payload_update_status(struct drm_dp_aux *aux)
> +{
> +	int ret;
> +	u8 status;
> +
> +	ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
> +	if (ret < 0)
> +		return ret;
> +
> +	return status;
> +}
> +
> +/**
> + * drm_dp_dpcd_poll_act_handled() - Polls for ACT handled status.
> + * @aux: DisplayPort AUX channel
> + * @timeout_ms: Timeout in ms
> + *
> + * Tries waiting for the sink to finish updating its payload table by polling
> + * for the ACT handled bit for up to @timeout_ms milliseconds, defaulting to
> + * 3000 ms if 0.
> + *
> + * Returns:
> + * 0 if the ACT was handled in time, negative error code on failure.
> + */
> +int drm_dp_dpcd_poll_act_handled(struct drm_dp_aux *aux, int timeout_ms)

I wonder if it'd make sense to namespace these helpers using ll_mtp or mtp.

> +{
> +	int ret, status;
> +

Extra w/s.

Regardless of the namespace comment:

Reviewed-by: Imre Deak <imre.deak@intel.com>

> +	/* default to 3 seconds, this is arbitrary */
> +	timeout_ms = timeout_ms ?: 3000;
> +
> +	ret = readx_poll_timeout(read_payload_update_status, aux, status,
> +				 status & DP_PAYLOAD_ACT_HANDLED || status < 0,
> +				 200, timeout_ms * USEC_PER_MSEC);
> +	if (ret < 0 && status >= 0) {
> +		drm_err(aux->drm_dev, "Failed to get ACT after %d ms, last status: %02x\n",
> +			timeout_ms, status);
> +		return -EINVAL;
> +	} else if (status < 0) {
> +		/*
> +		 * Failure here isn't unexpected - the hub may have
> +		 * just been unplugged
> +		 */
> +		drm_dbg_kms(aux->drm_dev, "Failed to read payload table status: %d\n", status);
> +		return status;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_dpcd_poll_act_handled);
> +
>  static bool is_edid_digital_input_dp(const struct drm_edid *drm_edid)
>  {
>  	/* FIXME: get rid of drm_edid_raw() */
> diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> index ac90118b9e7a..2bdbc1eb282b 100644
> --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> @@ -29,7 +29,6 @@
>  #include <linux/random.h>
>  #include <linux/sched.h>
>  #include <linux/seq_file.h>
> -#include <linux/iopoll.h>
>  
>  #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
>  #include <linux/stacktrace.h>
> @@ -4723,18 +4722,6 @@ static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
>  	return ret;
>  }
>  
> -static int do_get_act_status(struct drm_dp_aux *aux)
> -{
> -	int ret;
> -	u8 status;
> -
> -	ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
> -	if (ret < 0)
> -		return ret;
> -
> -	return status;
> -}
> -
>  /**
>   * drm_dp_check_act_status() - Polls for ACT handled status.
>   * @mgr: manager to use
> @@ -4752,28 +4739,9 @@ int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
>  	 * There doesn't seem to be any recommended retry count or timeout in
>  	 * the MST specification. Since some hubs have been observed to take
>  	 * over 1 second to update their payload allocations under certain
> -	 * conditions, we use a rather large timeout value.
> +	 * conditions, we use a rather large timeout value of 3 seconds.
>  	 */
> -	const int timeout_ms = 3000;
> -	int ret, status;
> -
> -	ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
> -				 status & DP_PAYLOAD_ACT_HANDLED || status < 0,
> -				 200, timeout_ms * USEC_PER_MSEC);
> -	if (ret < 0 && status >= 0) {
> -		drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n",
> -			timeout_ms, status);
> -		return -EINVAL;
> -	} else if (status < 0) {
> -		/*
> -		 * Failure here isn't unexpected - the hub may have
> -		 * just been unplugged
> -		 */
> -		drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status);
> -		return status;
> -	}
> -
> -	return 0;
> +	return drm_dp_dpcd_poll_act_handled(mgr->aux, 3000);
>  }
>  EXPORT_SYMBOL(drm_dp_check_act_status);
>  
> diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h
> index 279624833ea9..38eea21d1082 100644
> --- a/include/drm/display/drm_dp_helper.h
> +++ b/include/drm/display/drm_dp_helper.h
> @@ -567,6 +567,8 @@ int drm_dp_dpcd_read_phy_link_status(struct drm_dp_aux *aux,
>  				     enum drm_dp_phy dp_phy,
>  				     u8 link_status[DP_LINK_STATUS_SIZE]);
>  
> +int drm_dp_dpcd_poll_act_handled(struct drm_dp_aux *aux, int timeout_ms);
> +
>  bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux,
>  				    u8 real_edid_checksum);
>  
> -- 
> 2.39.5
>
Imre Deak Nov. 20, 2024, 3:18 p.m. UTC | #2
On Wed, Nov 20, 2024 at 04:59:43PM +0200, Imre Deak wrote:
> On Mon, Nov 18, 2024 at 05:14:52PM +0200, Jani Nikula wrote:
> > SST with 128b/132b channel coding needs this too. Extract to a separate
> > helper, independent of MST.
> > 
> > Pass timeout in as a parameter, anticipating that we can reduce the
> > timeout for SST.
> 
> I wish there was a DP Standard section making the above clear,
> but I suppose we just deduct that except of the side-band messaging,
> every other payload programming and ACT signaling is required for
> 128b/132b SST.
> 
> > 
> 
> Cc: Lyude Paul <lyude@redhat.com>
> 
> > Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> > ---
> >  drivers/gpu/drm/display/drm_dp_helper.c       | 54 ++++++++++++++++++-
> >  drivers/gpu/drm/display/drm_dp_mst_topology.c | 36 +------------
> >  include/drm/display/drm_dp_helper.h           |  2 +
> >  3 files changed, 57 insertions(+), 35 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
> > index 6ee51003de3c..b7e03bf02cd8 100644
> > --- a/drivers/gpu/drm/display/drm_dp_helper.c
> > +++ b/drivers/gpu/drm/display/drm_dp_helper.c
> > @@ -22,15 +22,16 @@
> >  
> >  #include <linux/backlight.h>
> >  #include <linux/delay.h>
> > +#include <linux/dynamic_debug.h>
> >  #include <linux/errno.h>
> >  #include <linux/i2c.h>
> >  #include <linux/init.h>
> > +#include <linux/iopoll.h>
> >  #include <linux/kernel.h>
> >  #include <linux/module.h>
> >  #include <linux/sched.h>
> >  #include <linux/seq_file.h>
> >  #include <linux/string_helpers.h>
> > -#include <linux/dynamic_debug.h>
> >  
> >  #include <drm/display/drm_dp_helper.h>
> >  #include <drm/display/drm_dp_mst_helper.h>
> > @@ -779,6 +780,57 @@ int drm_dp_dpcd_read_phy_link_status(struct drm_dp_aux *aux,
> >  }
> >  EXPORT_SYMBOL(drm_dp_dpcd_read_phy_link_status);
> >  
> > +static int read_payload_update_status(struct drm_dp_aux *aux)
> > +{
> > +	int ret;
> > +	u8 status;
> > +
> > +	ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return status;
> > +}
> > +
> > +/**
> > + * drm_dp_dpcd_poll_act_handled() - Polls for ACT handled status.
> > + * @aux: DisplayPort AUX channel
> > + * @timeout_ms: Timeout in ms
> > + *
> > + * Tries waiting for the sink to finish updating its payload table by polling
> > + * for the ACT handled bit for up to @timeout_ms milliseconds, defaulting to
> > + * 3000 ms if 0.
> > + *
> > + * Returns:
> > + * 0 if the ACT was handled in time, negative error code on failure.
> > + */
> > +int drm_dp_dpcd_poll_act_handled(struct drm_dp_aux *aux, int timeout_ms)
> 
> I wonder if it'd make sense to namespace these helpers using ll_mtp or mtp.
> 
> > +{
> > +	int ret, status;
> > +
> 
> Extra w/s.

Ah nvm, timeout_ms is a function param so new is needed.

> 
> Regardless of the namespace comment:
> 
> Reviewed-by: Imre Deak <imre.deak@intel.com>
> 
> > +	/* default to 3 seconds, this is arbitrary */
> > +	timeout_ms = timeout_ms ?: 3000;
> > +
> > +	ret = readx_poll_timeout(read_payload_update_status, aux, status,
> > +				 status & DP_PAYLOAD_ACT_HANDLED || status < 0,
> > +				 200, timeout_ms * USEC_PER_MSEC);
> > +	if (ret < 0 && status >= 0) {
> > +		drm_err(aux->drm_dev, "Failed to get ACT after %d ms, last status: %02x\n",
> > +			timeout_ms, status);
> > +		return -EINVAL;
> > +	} else if (status < 0) {
> > +		/*
> > +		 * Failure here isn't unexpected - the hub may have
> > +		 * just been unplugged
> > +		 */
> > +		drm_dbg_kms(aux->drm_dev, "Failed to read payload table status: %d\n", status);
> > +		return status;
> > +	}
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL(drm_dp_dpcd_poll_act_handled);
> > +
> >  static bool is_edid_digital_input_dp(const struct drm_edid *drm_edid)
> >  {
> >  	/* FIXME: get rid of drm_edid_raw() */
> > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > index ac90118b9e7a..2bdbc1eb282b 100644
> > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > @@ -29,7 +29,6 @@
> >  #include <linux/random.h>
> >  #include <linux/sched.h>
> >  #include <linux/seq_file.h>
> > -#include <linux/iopoll.h>
> >  
> >  #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
> >  #include <linux/stacktrace.h>
> > @@ -4723,18 +4722,6 @@ static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
> >  	return ret;
> >  }
> >  
> > -static int do_get_act_status(struct drm_dp_aux *aux)
> > -{
> > -	int ret;
> > -	u8 status;
> > -
> > -	ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
> > -	if (ret < 0)
> > -		return ret;
> > -
> > -	return status;
> > -}
> > -
> >  /**
> >   * drm_dp_check_act_status() - Polls for ACT handled status.
> >   * @mgr: manager to use
> > @@ -4752,28 +4739,9 @@ int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
> >  	 * There doesn't seem to be any recommended retry count or timeout in
> >  	 * the MST specification. Since some hubs have been observed to take
> >  	 * over 1 second to update their payload allocations under certain
> > -	 * conditions, we use a rather large timeout value.
> > +	 * conditions, we use a rather large timeout value of 3 seconds.
> >  	 */
> > -	const int timeout_ms = 3000;
> > -	int ret, status;
> > -
> > -	ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
> > -				 status & DP_PAYLOAD_ACT_HANDLED || status < 0,
> > -				 200, timeout_ms * USEC_PER_MSEC);
> > -	if (ret < 0 && status >= 0) {
> > -		drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n",
> > -			timeout_ms, status);
> > -		return -EINVAL;
> > -	} else if (status < 0) {
> > -		/*
> > -		 * Failure here isn't unexpected - the hub may have
> > -		 * just been unplugged
> > -		 */
> > -		drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status);
> > -		return status;
> > -	}
> > -
> > -	return 0;
> > +	return drm_dp_dpcd_poll_act_handled(mgr->aux, 3000);
> >  }
> >  EXPORT_SYMBOL(drm_dp_check_act_status);
> >  
> > diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h
> > index 279624833ea9..38eea21d1082 100644
> > --- a/include/drm/display/drm_dp_helper.h
> > +++ b/include/drm/display/drm_dp_helper.h
> > @@ -567,6 +567,8 @@ int drm_dp_dpcd_read_phy_link_status(struct drm_dp_aux *aux,
> >  				     enum drm_dp_phy dp_phy,
> >  				     u8 link_status[DP_LINK_STATUS_SIZE]);
> >  
> > +int drm_dp_dpcd_poll_act_handled(struct drm_dp_aux *aux, int timeout_ms);
> > +
> >  bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux,
> >  				    u8 real_edid_checksum);
> >  
> > -- 
> > 2.39.5
> >
diff mbox series

Patch

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
index 6ee51003de3c..b7e03bf02cd8 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -22,15 +22,16 @@ 
 
 #include <linux/backlight.h>
 #include <linux/delay.h>
+#include <linux/dynamic_debug.h>
 #include <linux/errno.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
+#include <linux/iopoll.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/seq_file.h>
 #include <linux/string_helpers.h>
-#include <linux/dynamic_debug.h>
 
 #include <drm/display/drm_dp_helper.h>
 #include <drm/display/drm_dp_mst_helper.h>
@@ -779,6 +780,57 @@  int drm_dp_dpcd_read_phy_link_status(struct drm_dp_aux *aux,
 }
 EXPORT_SYMBOL(drm_dp_dpcd_read_phy_link_status);
 
+static int read_payload_update_status(struct drm_dp_aux *aux)
+{
+	int ret;
+	u8 status;
+
+	ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
+	if (ret < 0)
+		return ret;
+
+	return status;
+}
+
+/**
+ * drm_dp_dpcd_poll_act_handled() - Polls for ACT handled status.
+ * @aux: DisplayPort AUX channel
+ * @timeout_ms: Timeout in ms
+ *
+ * Tries waiting for the sink to finish updating its payload table by polling
+ * for the ACT handled bit for up to @timeout_ms milliseconds, defaulting to
+ * 3000 ms if 0.
+ *
+ * Returns:
+ * 0 if the ACT was handled in time, negative error code on failure.
+ */
+int drm_dp_dpcd_poll_act_handled(struct drm_dp_aux *aux, int timeout_ms)
+{
+	int ret, status;
+
+	/* default to 3 seconds, this is arbitrary */
+	timeout_ms = timeout_ms ?: 3000;
+
+	ret = readx_poll_timeout(read_payload_update_status, aux, status,
+				 status & DP_PAYLOAD_ACT_HANDLED || status < 0,
+				 200, timeout_ms * USEC_PER_MSEC);
+	if (ret < 0 && status >= 0) {
+		drm_err(aux->drm_dev, "Failed to get ACT after %d ms, last status: %02x\n",
+			timeout_ms, status);
+		return -EINVAL;
+	} else if (status < 0) {
+		/*
+		 * Failure here isn't unexpected - the hub may have
+		 * just been unplugged
+		 */
+		drm_dbg_kms(aux->drm_dev, "Failed to read payload table status: %d\n", status);
+		return status;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_dpcd_poll_act_handled);
+
 static bool is_edid_digital_input_dp(const struct drm_edid *drm_edid)
 {
 	/* FIXME: get rid of drm_edid_raw() */
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index ac90118b9e7a..2bdbc1eb282b 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -29,7 +29,6 @@ 
 #include <linux/random.h>
 #include <linux/sched.h>
 #include <linux/seq_file.h>
-#include <linux/iopoll.h>
 
 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
 #include <linux/stacktrace.h>
@@ -4723,18 +4722,6 @@  static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
 	return ret;
 }
 
-static int do_get_act_status(struct drm_dp_aux *aux)
-{
-	int ret;
-	u8 status;
-
-	ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
-	if (ret < 0)
-		return ret;
-
-	return status;
-}
-
 /**
  * drm_dp_check_act_status() - Polls for ACT handled status.
  * @mgr: manager to use
@@ -4752,28 +4739,9 @@  int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
 	 * There doesn't seem to be any recommended retry count or timeout in
 	 * the MST specification. Since some hubs have been observed to take
 	 * over 1 second to update their payload allocations under certain
-	 * conditions, we use a rather large timeout value.
+	 * conditions, we use a rather large timeout value of 3 seconds.
 	 */
-	const int timeout_ms = 3000;
-	int ret, status;
-
-	ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
-				 status & DP_PAYLOAD_ACT_HANDLED || status < 0,
-				 200, timeout_ms * USEC_PER_MSEC);
-	if (ret < 0 && status >= 0) {
-		drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n",
-			timeout_ms, status);
-		return -EINVAL;
-	} else if (status < 0) {
-		/*
-		 * Failure here isn't unexpected - the hub may have
-		 * just been unplugged
-		 */
-		drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status);
-		return status;
-	}
-
-	return 0;
+	return drm_dp_dpcd_poll_act_handled(mgr->aux, 3000);
 }
 EXPORT_SYMBOL(drm_dp_check_act_status);
 
diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h
index 279624833ea9..38eea21d1082 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -567,6 +567,8 @@  int drm_dp_dpcd_read_phy_link_status(struct drm_dp_aux *aux,
 				     enum drm_dp_phy dp_phy,
 				     u8 link_status[DP_LINK_STATUS_SIZE]);
 
+int drm_dp_dpcd_poll_act_handled(struct drm_dp_aux *aux, int timeout_ms);
+
 bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux,
 				    u8 real_edid_checksum);