From: Nicholas Kazlauskas nicholas.kazlauskas@amd.com
commit 94ebc035456a4ccacfbbef60c444079a256623ad upstream.
[Why] When trying to lightup two 4k60 non-DSC displays behind a branch device that supports DSC we can't lightup both at once due to bandwidth limitations - each requires 48 VCPI slots but we only have 63.
[How] The workaround already exists in the code but is guarded by a CONFIG that cannot be set by the user and shouldn't need to be.
Check for specific branch device IDs to device whether to enable the workaround for multiple display scenarios.
Reviewed-by: Hersen Wu hersenxs.wu@amd.com Acked-by: Bhawanpreet Lakha Bhawanpreet.Lakha@amd.com Signed-off-by: Nicholas Kazlauskas nicholas.kazlauskas@amd.com Tested-by: Daniel Wheeler daniel.wheeler@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 20 +++++++++--- 1 file changed, 16 insertions(+), 4 deletions(-)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -36,6 +36,8 @@ #include "dm_helpers.h"
#include "dc_link_ddc.h" +#include "ddc_service_types.h" +#include "dpcd_defs.h"
#include "i2caux_interface.h" #if defined(CONFIG_DEBUG_FS) @@ -152,6 +154,16 @@ static const struct drm_connector_funcs };
#if defined(CONFIG_DRM_AMD_DC_DCN) +static bool needs_dsc_aux_workaround(struct dc_link *link) +{ + if (link->dpcd_caps.branch_dev_id == DP_BRANCH_DEVICE_ID_90CC24 && + (link->dpcd_caps.dpcd_rev.raw == DPCD_REV_14 || link->dpcd_caps.dpcd_rev.raw == DPCD_REV_12) && + link->dpcd_caps.sink_count.bits.SINK_COUNT >= 2) + return true; + + return false; +} + static bool validate_dsc_caps_on_connector(struct amdgpu_dm_connector *aconnector) { struct dc_sink *dc_sink = aconnector->dc_sink; @@ -159,7 +171,7 @@ static bool validate_dsc_caps_on_connect u8 dsc_caps[16] = { 0 };
aconnector->dsc_aux = drm_dp_mst_dsc_aux_for_port(port); -#if defined(CONFIG_HP_HOOK_WORKAROUND) + /* * drm_dp_mst_dsc_aux_for_port() will return NULL for certain configs * because it only check the dsc/fec caps of the "port variable" and not the dock @@ -169,10 +181,10 @@ static bool validate_dsc_caps_on_connect * Workaround: explicitly check the use case above and use the mst dock's aux as dsc_aux * */ - - if (!aconnector->dsc_aux && !port->parent->port_parent) + if (!aconnector->dsc_aux && !port->parent->port_parent && + needs_dsc_aux_workaround(aconnector->dc_link)) aconnector->dsc_aux = &aconnector->mst_port->dm_dp_aux.aux; -#endif + if (!aconnector->dsc_aux) return false;