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drm/amdgpu: Respect max pixel clock for HDMI and DVI-D (v2)

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Update the legacy (non-DC) display code to respect the maximum
pixel clock for HDMI and DVI-D. Reject modes that would require
a higher pixel clock than can be supported.

Also update the maximum supported HDMI clock value depending on
the ASIC type.

For reference, see the DC code:
check max_hdmi_pixel_clock in dce*_resource.c

v2:
Fix maximum clocks for DVI-D and DVI/HDMI adapters.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Timur Kristóf 2025-08-28 16:50:36 +02:00 committed by Alex Deucher
parent 220b2bd529
commit 585b2f685c
1 changed files with 44 additions and 13 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

57
drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
View file

@ -1195,29 +1195,60 @@ static void amdgpu_connector_dvi_force(struct drm_connector *connector)
amdgpu_connector->use_digital = true;
}
/**
* Returns the maximum supported HDMI (TMDS) pixel clock in KHz.
*/
static int amdgpu_max_hdmi_pixel_clock(const struct amdgpu_device *adev)
{
if (adev->asic_type >= CHIP_POLARIS10)
return 600000;
else if (adev->asic_type >= CHIP_TONGA)
return 300000;
else
return 297000;
}
/**
* Validates the given display mode on DVI and HDMI connectors,
* including analog signals on DVI-I.
*/
static enum drm_mode_status amdgpu_connector_dvi_mode_valid(struct drm_connector *connector,
const struct drm_display_mode *mode)
{
struct drm_device *dev = connector->dev;
struct amdgpu_device *adev = drm_to_adev(dev);
struct amdgpu_connector *amdgpu_connector = to_amdgpu_connector(connector);
const int max_hdmi_pixel_clock = amdgpu_max_hdmi_pixel_clock(adev);
const int max_dvi_single_link_pixel_clock = 165000;
int max_digital_pixel_clock_khz;
/* XXX check mode bandwidth */
if (amdgpu_connector->use_digital && (mode->clock > 165000)) {
if ((amdgpu_connector->connector_object_id == CONNECTOR_OBJECT_ID_DUAL_LINK_DVI_I) ||
(amdgpu_connector->connector_object_id == CONNECTOR_OBJECT_ID_DUAL_LINK_DVI_D) ||
(amdgpu_connector->connector_object_id == CONNECTOR_OBJECT_ID_HDMI_TYPE_B)) {
return MODE_OK;
} else if (connector->display_info.is_hdmi) {
/* HDMI 1.3+ supports max clock of 340 Mhz */
if (mode->clock > 340000)
return MODE_CLOCK_HIGH;
else
return MODE_OK;
} else {
return MODE_CLOCK_HIGH;
if (amdgpu_connector->use_digital) {
switch (amdgpu_connector->connector_object_id) {
case CONNECTOR_OBJECT_ID_HDMI_TYPE_A:
max_digital_pixel_clock_khz = max_hdmi_pixel_clock;
break;
case CONNECTOR_OBJECT_ID_SINGLE_LINK_DVI_I:
case CONNECTOR_OBJECT_ID_SINGLE_LINK_DVI_D:
max_digital_pixel_clock_khz = max_dvi_single_link_pixel_clock;
break;
case CONNECTOR_OBJECT_ID_DUAL_LINK_DVI_I:
case CONNECTOR_OBJECT_ID_DUAL_LINK_DVI_D:
case CONNECTOR_OBJECT_ID_HDMI_TYPE_B:
max_digital_pixel_clock_khz = max_dvi_single_link_pixel_clock * 2;
break;
}
/* When the display EDID claims that it's an HDMI display,
* we use the HDMI encoder mode of the display HW,
* so we should verify against the max HDMI clock here.
*/
if (connector->display_info.is_hdmi)
max_digital_pixel_clock_khz = max_hdmi_pixel_clock;
if (mode->clock > max_digital_pixel_clock_khz)
return MODE_CLOCK_HIGH;
}
/* check against the max pixel clock */