linux-stable/drivers/gpu/drm/drm_dp_mst_topology_internal.h
Lyude Paul 2f015ec6ea drm/dp_mst: Add sideband down request tracing + selftests
Unfortunately the DP MST helpers do not have much in the way of
debugging utilities. So, let's add some!

This adds basic debugging output for down sideband requests that we send
from the driver, so that we can actually discern what's happening when
sideband requests timeout.

Since there wasn't really a good way of testing that any of this worked,
I ended up writing simple selftests that lightly test sideband message
encoding and decoding as well. Enjoy!

Changes since v1:
* Clean up DO_TEST() and sideband_msg_req_encode_decode() - danvet
* Get rid of pr_fmt(), just define a prefix string instead and use
  drm_printf()
* Check highest bit of VCPI in drm_dp_decode_sideband_req() - danvet
* Make the switch case order between drm_dp_decode_sideband_req() and
  drm_dp_encode_sideband_req() the same - danvet
* Only check DRM_UT_DP - danvet
* Clean up sideband_msg_req_equal() from selftests a bit, and add
  comments explaining why we can't just use memcmp - danvet

Cc: Juston Li <juston.li@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Harry Wentland <hwentlan@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190903204645.25487-8-lyude@redhat.com
2019-09-03 19:30:06 -04:00

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C

/* SPDX-License-Identifier: GPL-2.0-only
*
* Declarations for DP MST related functions which are only used in selftests
*
* Copyright © 2018 Red Hat
* Authors:
* Lyude Paul <lyude@redhat.com>
*/
#ifndef _DRM_DP_MST_HELPER_INTERNAL_H_
#define _DRM_DP_MST_HELPER_INTERNAL_H_
#include <drm/drm_dp_mst_helper.h>
void
drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
struct drm_dp_sideband_msg_tx *raw);
int drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
struct drm_dp_sideband_msg_req_body *req);
void
drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
int indent, struct drm_printer *printer);
#endif /* !_DRM_DP_MST_HELPER_INTERNAL_H_ */