Commit f2663f70 authored by Jani Nikula's avatar Jani Nikula
Browse files

drm/dp: extract drm_dp_dpcd_poll_act_handled() 



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.

v2: Clean up kernel-doc a bit

Cc: Lyude Paul <lyude@redhat.com>
Reviewed-by: default avatarImre Deak <imre.deak@intel.com>
Reviewed-by: default avatarLyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/459fd3e96a55a8ea8ada8d27d93eaa24c235f9c1.1733238941.git.jani.nikula@intel.com


Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
parent 39b1acfd

drivers/gpu/drm/display/drm_dp_helper.c

+53 −1
Original line number Diff line number Diff line
@@ -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() - Poll for ACT handled status

 * @aux: DisplayPort AUX channel

 * @timeout_ms: Timeout in ms

 *

 * Try waiting for the sink to finish updating its payload table by polling for

 * the ACT handled bit of DP_PAYLOAD_TABLE_UPDATE_STATUS 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() */

drivers/gpu/drm/display/drm_dp_mst_topology.c

+2 −34
Original line number Diff line number Diff line
@@ -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.

	 */

	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

	 * conditions, we use a rather large timeout value of 3 seconds.

	 */

		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);

include/drm/display/drm_dp_helper.h

+2 −0
Original line number Diff line number Diff line
@@ -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);