On Wed, Sep 25, 2024 at 12:11 AM Jessica Zhang <quic_jesszhan@xxxxxxxxxxx> wrote: > > > > On 9/23/2024 7:13 PM, zhaoxiong lv wrote: > > On Tue, Sep 24, 2024 at 5:14 AM Jessica Zhang <quic_jesszhan@xxxxxxxxxxx> wrote: > >> > >> > >> > >> On 9/23/2024 6:42 AM, Zhaoxiong Lv wrote: > >>> In MTK chips, if the system starts suspending before the DRM runtime > >>> resume has not completed, there is a possibility of a black screen > >>> after waking the machine. Reduce the disable delay resolves this issue, > >> > >> Hi Zhaoxiong, > >> > >> Do you mean "if the system starts suspending before the DRM runtime > >> resume *has* completed" here? > > > > Hi Jessica > > > > Sorry, my description may not be clear enough. It should be when the > > DRM runtime resume has not yet completed and the system enters sleep > > mode at the same time. > > Got it, yes I think the reworded explanation in your reply is much clearer. > > > > > > >> > >>> > >>> The "backlight_off_to_display_off_delay_ms" was added between > >>> "backlight off" and "display off" to prevent "display off" from being > >>> executed when the backlight is not fully powered off, which may cause > >>> a white screen. However, we removed this > >>> "backlight_off_to_display_off_delay_ms" and found that this situation > >>> did not occur. Therefore, in order to solve the problem mentioned > >>> above, we We reduced it from 100ms to 3ms (tCMD_OFF >= 1ms). > >> > >> So from my understanding of this paragraph, > >> `backlight_off_to_display_off_delay_ms` was added to prevent the display > >> powering off before backlight is fully powered off. You recently tested > >> dropping this completely and saw no issue with this. > >> > >> If that's the case, why not drop this delay completely? > >> > >> Thanks, > >> > >> Jessica Zhang > > > > Yes, there are currently no other issue after removing this delay. > > The reason why I didn't completely remove this delay is because the > > panel spec states that a delay of more than 1ms (tCMD_OFF >= 1ms) is > > required when entering diaplay_off (0x28H), so I reserved 3ms. > > Thanks for the clarification -- I see why you included the "(tCMD_OFF >= > 1ms)" part now. Can you please specify in the commit message that the > tCMD_OFF delay requirement is from the spec? > > Also can you remove the extra "We" in "we We reduced it from 100ms to 3ms"? > > Thanks, > > Jessica Zhang OK, thanks for your correction, we will modify the commit message in the next patch. > > > > >> > >>> > >>> This is the timing specification for the two panels: > >>> 1. Kingdisplay panel timing spec: > >>> https://github.com/KD54183/-JD9365DA_Power-On-Off-Sequence_V0120240923 > >>> 2. LMFBX101117480 timing spec: https://github.com/chiohsin-lo/TDY-JD_LIB > >>> > >>> > >>> Fixes: 2b976ad760dc ("drm/panel: jd9365da: Support for kd101ne3-40ti MIPI-DSI panel") > >>> Fixes: c4ce398cf18a ("drm/panel: jd9365da: Support for Melfas lmfbx101117480 MIPI-DSI panel") > >>> > >>> Signed-off-by: Zhaoxiong Lv <lvzhaoxiong@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> > >>> --- > >>> Changes between V2 and V1: > >>> - 1. Modify the commit message > >>> - 2. Modify the value of backlight_off_to_display_off_delay_ms. > >>> v1: https://lore.kernel.org/all/20240915080830.11318-2-lvzhaoxiong@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ > >>> --- > >>> drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c | 4 ++-- > >>> 1 file changed, 2 insertions(+), 2 deletions(-) > >>> > >>> diff --git a/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c b/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c > >>> index 44897e5218a6..486aa20e5518 100644 > >>> --- a/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c > >>> +++ b/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c > >>> @@ -858,7 +858,7 @@ static const struct jadard_panel_desc kingdisplay_kd101ne3_40ti_desc = { > >>> .reset_before_power_off_vcioo = true, > >>> .vcioo_to_lp11_delay_ms = 5, > >>> .lp11_to_reset_delay_ms = 10, > >>> - .backlight_off_to_display_off_delay_ms = 100, > >>> + .backlight_off_to_display_off_delay_ms = 3, > >>> .display_off_to_enter_sleep_delay_ms = 50, > >>> .enter_sleep_to_reset_down_delay_ms = 100, > >>> }; > >>> @@ -1109,7 +1109,7 @@ static const struct jadard_panel_desc melfas_lmfbx101117480_desc = { > >>> .reset_before_power_off_vcioo = true, > >>> .vcioo_to_lp11_delay_ms = 5, > >>> .lp11_to_reset_delay_ms = 10, > >>> - .backlight_off_to_display_off_delay_ms = 100, > >>> + .backlight_off_to_display_off_delay_ms = 3, > >>> .display_off_to_enter_sleep_delay_ms = 50, > >>> .enter_sleep_to_reset_down_delay_ms = 100, > >>> }; > >>> -- > >>> 2.17.1 > >>> > >> >
