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297a4833a6
On DCE 6, DP audio was not working. However, it worked when an HDMI monitor was also plugged in. Looking at dce_aud_wall_dto_setup it seems that the main difference is that we use DTO1 when only DP is plugged in. When programming DTO1, it uses audio_dto_source_clock_in_khz which is set from get_dp_ref_freq_khz The dce60_get_dp_ref_freq_khz implementation looks incorrect, because DENTIST_DISPCLK_CNTL seems to be always zero on DCE 6, so it isn't usable. I compared dce60_get_dp_ref_freq_khz to the legacy display code, specifically dce_v6_0_audio_set_dto, and it turns out that in case of DCE 6, it needs to use the display clock. With that, DP audio started working on Pitcairn, Oland and Cape Verde. However, it still didn't work on Tahiti. Despite having the same DCE version, Tahiti seems to have a different audio device. After some trial and error I realized that it works with the default display clock as reported by the VBIOS, not the current display clock. The patch was tested on all four SI GPUs: * Pitcairn (DCE 6.0) * Oland (DCE 6.4) * Cape Verde (DCE 6.0) * Tahiti (DCE 6.0 but different) The testing was done on Samsung Odyssey G7 LS28BG700EPXEN on each of the above GPUs, at the following settings: * 4K 60 Hz * 1080p 60 Hz * 1080p 144 Hz Acked-by: Alex Deucher <alexander.deucher@amd.com> Reviewed-by: Rodrigo Siqueira <siqueira@igalia.com> Signed-off-by: Timur Kristóf <timur.kristof@gmail.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> (cherry picked from commit 645cc7863da5de700547d236697dffd6760cf051) Cc: stable@vger.kernel.org |
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