drm/amd/display: Add debugfs dpcd interface

Browse source

[Why]
We need arbitrary read/write over DP AUX DPCD
for debugging

[How]
Three debugfs entries

Set the target address by writing to
"aux_dpcd_address"
(The first four bytes written are used)

Set the transaction size in bytes by writing to
"aux_dpcd_size"
(The first four bytes written are used)

Start a transaction by reading/writing
"aux_dpcd_data"

Do note: there is no concerrency protection at all
Accessing these entries in quick succession can lead
to strange behaviour

Signed-off-by: David Francis <David.Francis@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

...

This commit is contained in:

David Francis 2019-03-05 10:04:15 -05:00 • committed by Alex Deucher

parent c7ba3653e9

commit f258fee6c3

3 changed files with 112 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

2

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

View file

4

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h

View file

107

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c

View file