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drm/amd/display: Get backlight from PWM if DMCU is not initialized

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On Carrizo/Stoney systems we set backlight through panel_cntl, i.e.
directly via the PWM registers, if DMCU is not initialized. We
always read it back through ABM registers which leads to a
mismatch and forces atomic_commit to program the backlight
each time.

Instead make sure we use the same logic for backlight readback,
i.e. read it from panel_cntl if DMCU is not initialized.

We also need to remove some extraneous and incorrect calculations
at the end of dce_get_16_bit_backlight_from_pwm.

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1666
Cc: stable@vger.kernel.org

Reviewed-by: Josip Pavic <josip.pavic@amd.com>
Acked-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Harry Wentland
2021-08-16 15:57:12 -04:00
committed by Alex Deucher
parent fb932dfeb8
commit 9987fbb368
2 changed files with 12 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
drivers/gpu/drm/amd/display/dc/core/dc_link.c
View File

@@ -2586,13 +2586,21 @@ static struct abm *get_abm_from_stream_res(const struct dc_link *link)
int dc_link_get_backlight_level(const struct dc_link *link)
{
struct abm *abm = get_abm_from_stream_res(link);
struct panel_cntl *panel_cntl = link->panel_cntl;
struct dc *dc = link->ctx->dc;
struct dmcu *dmcu = dc->res_pool->dmcu;
bool fw_set_brightness = true;
if (abm == NULL || abm->funcs->get_current_backlight == NULL)
if (dmcu)
fw_set_brightness = dmcu->funcs->is_dmcu_initialized(dmcu);
if (!fw_set_brightness && panel_cntl->funcs->get_current_backlight)
return panel_cntl->funcs->get_current_backlight(panel_cntl);
else if (abm != NULL && abm->funcs->get_current_backlight != NULL)
return (int) abm->funcs->get_current_backlight(abm);
else
return DC_ERROR_UNEXPECTED;
return (int) abm->funcs->get_current_backlight(abm);
}
int dc_link_get_target_backlight_pwm(const struct dc_link *link)

10
drivers/gpu/drm/amd/display/dc/dce/dce_panel_cntl.c
View File

@@ -49,7 +49,6 @@
static unsigned int dce_get_16_bit_backlight_from_pwm(struct panel_cntl *panel_cntl)
{
uint64_t current_backlight;
uint32_t round_result;
uint32_t bl_period, bl_int_count;
uint32_t bl_pwm, fractional_duty_cycle_en;
uint32_t bl_period_mask, bl_pwm_mask;
@@ -84,15 +83,6 @@ static unsigned int dce_get_16_bit_backlight_from_pwm(struct panel_cntl *panel_c
current_backlight = div_u64(current_backlight, bl_period);
current_backlight = (current_backlight + 1) >> 1;
current_backlight = (uint64_t)(current_backlight) * bl_period;
round_result = (uint32_t)(current_backlight & 0xFFFFFFFF);
round_result = (round_result >> (bl_int_count-1)) & 1;
current_backlight >>= bl_int_count;
current_backlight += round_result;
return (uint32_t)(current_backlight);
}