From: George Shen <george.s...@amd.com>
[Why]
Certain small HBlank timings may not have a large enough HBlank to
support audio when low bpp DSC is enabled. HBlank expansion by the
source can solve this problem, but requires the branch/sink to support
HBlank reduction.
[How]
Update DPMS sequence to call DM to perform DPCD write to enable HBlank
reduction on the branch/sink. Add stub in dm_helpers to be implemented
later.
Reviewed-by: Michael Strauss <michael.stra...@amd.com>
Reviewed-by: Wenjing Liu <wenjing....@amd.com>
Signed-off-by: George Shen <george.s...@amd.com>
Signed-off-by: Roman Li <roman...@amd.com>
Tested-by: Daniel Wheeler <daniel.whee...@amd.com>
---
.../amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 6 ++++++
drivers/gpu/drm/amd/display/dc/dm_helpers.h | 5 +++++
drivers/gpu/drm/amd/display/dc/link/link_dpms.c | 17 +++++++++++++++++
3 files changed, 28 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
index 6cbbb71d752b..fbd80d8545a8 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
@@ -885,6 +885,12 @@ bool dm_helpers_dp_write_dsc_enable(
return ret;
}
+bool dm_helpers_dp_write_hblank_reduction(struct dc_context *ctx, const struct
dc_stream_state *stream)
+{
+ // TODO
+ return false;
+}
+
bool dm_helpers_is_dp_sink_present(struct dc_link *link)
{
bool dp_sink_present;
diff --git a/drivers/gpu/drm/amd/display/dc/dm_helpers.h
b/drivers/gpu/drm/amd/display/dc/dm_helpers.h
index 2e4a46f1b499..5efddd48d5c5 100644
--- a/drivers/gpu/drm/amd/display/dc/dm_helpers.h
+++ b/drivers/gpu/drm/amd/display/dc/dm_helpers.h
@@ -158,6 +158,11 @@ bool dm_helpers_dp_write_dsc_enable(
const struct dc_stream_state *stream,
bool enable
);
+
+bool dm_helpers_dp_write_hblank_reduction(
+ struct dc_context *ctx,
+ const struct dc_stream_state *stream);
+
bool dm_helpers_is_dp_sink_present(
struct dc_link *link);
diff --git a/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
b/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
index 6f3e7e182145..ae79dc213901 100644
--- a/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
+++ b/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
@@ -772,6 +772,20 @@ static bool dp_set_dsc_on_rx(struct pipe_ctx *pipe_ctx,
bool enable)
return result;
}
+static bool dp_set_hblank_reduction_on_rx(struct pipe_ctx *pipe_ctx)
+{
+ struct dc *dc = pipe_ctx->stream->ctx->dc;
+ struct dc_stream_state *stream = pipe_ctx->stream;
+ bool result = false;
+
+ if (dc_is_virtual_signal(stream->signal))
+ result = true;
+ else
+ result = dm_helpers_dp_write_hblank_reduction(dc->ctx, stream);
+ return result;
+}
+
+
/* The stream with these settings can be sent (unblanked) only after DSC was
enabled on RX first,
* i.e. after dp_enable_dsc_on_rx() had been called
*/
@@ -2599,6 +2613,9 @@ void link_set_dpms_on(
}
}
+ if (dc_is_dp_signal(pipe_ctx->stream->signal))
+ dp_set_hblank_reduction_on_rx(pipe_ctx);
+
if (pipe_ctx->stream->link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA)
allocate_usb4_bandwidth(pipe_ctx->stream);
--
2.34.1
