As made mention of in commit 099303e9a9bd ("drm/amd/display: eDP
intermittent black screen during PnP"), we need to turn off the
display's backlight before powering off an eDP display. Not doing so
will result in undefined behaviour according to the eDP spec. So, set
DCN301's edp_backlight_control() function pointer to
dce110_edp_backlight_control().

Cc: stable@vger.kernel.org
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2765
Fixes: 9c75891feef0 ("drm/amd/display: rework recent update PHY state commit")
Suggested-by: Swapnil Patel <swapnil.patel@amd.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
---
 drivers/gpu/drm/amd/display/dc/dcn301/dcn301_init.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn301/dcn301_init.c b/drivers/gpu/drm/amd/display/dc/dcn301/dcn301_init.c
index 257df8660b4c..61205cdbe2d5 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn301/dcn301_init.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn301/dcn301_init.c
@@ -75,6 +75,7 @@ static const struct hw_sequencer_funcs dcn301_funcs = {
 	.get_hw_state = dcn10_get_hw_state,
 	.clear_status_bits = dcn10_clear_status_bits,
 	.wait_for_mpcc_disconnect = dcn10_wait_for_mpcc_disconnect,
+	.edp_backlight_control = dce110_edp_backlight_control,
 	.edp_power_control = dce110_edp_power_control,
 	.edp_wait_for_hpd_ready = dce110_edp_wait_for_hpd_ready,
 	.set_cursor_position = dcn10_set_cursor_position,
-- 
2.41.0

On 2023-08-22 13:03, Hamza Mahfooz wrote:
> As made mention of in commit 099303e9a9bd ("drm/amd/display: eDP
> intermittent black screen during PnP"), we need to turn off the
> display's backlight before powering off an eDP display. Not doing so
> will result in undefined behaviour according to the eDP spec. So, set
> DCN301's edp_backlight_control() function pointer to
> dce110_edp_backlight_control().
> 
> Cc: stable@vger.kernel.org
> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2765
> Fixes: 9c75891feef0 ("drm/amd/display: rework recent update PHY state commit")
> Suggested-by: Swapnil Patel <swapnil.patel@amd.com>
> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>

Reviewed-by: Harry Wentland <harry.wentland@amd.com>

Harry

> ---
>  drivers/gpu/drm/amd/display/dc/dcn301/dcn301_init.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/dcn301/dcn301_init.c b/drivers/gpu/drm/amd/display/dc/dcn301/dcn301_init.c
> index 257df8660b4c..61205cdbe2d5 100644
> --- a/drivers/gpu/drm/amd/display/dc/dcn301/dcn301_init.c
> +++ b/drivers/gpu/drm/amd/display/dc/dcn301/dcn301_init.c
> @@ -75,6 +75,7 @@ static const struct hw_sequencer_funcs dcn301_funcs = {
>  	.get_hw_state = dcn10_get_hw_state,
>  	.clear_status_bits = dcn10_clear_status_bits,
>  	.wait_for_mpcc_disconnect = dcn10_wait_for_mpcc_disconnect,
> +	.edp_backlight_control = dce110_edp_backlight_control,
>  	.edp_power_control = dce110_edp_power_control,
>  	.edp_wait_for_hpd_ready = dce110_edp_wait_for_hpd_ready,
>  	.set_cursor_position = dcn10_set_cursor_position,