| Message ID | 20250411092307.238398-1-j-choudhary@ti.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | drm/bridge: ti-sn65dsi86: Add necessary DSI flags | expand |
Hi, On Fri, Apr 11, 2025 at 2:23 AM Jayesh Choudhary <j-choudhary@ti.com> wrote: > > Enable NO_EOT and SYNC flags for DSI to use VIDEO_SYNC_PULSE_MODE > with EOT disabled. Any chance you could add some details to this commit message? Your subject says that these flags are "necessary", but people have been using this driver successfully for many years now. Why did these flags suddenly become necessary and why were things working before? I'm not saying that we shouldn't use these flags, just trying to understand. I actually don't know a ton about these details in MIPI, so it would help me :-). > Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com> > --- > drivers/gpu/drm/bridge/ti-sn65dsi86.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c > index f72675766e01..8e9a7eb927da 100644 > --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c > @@ -707,7 +707,8 @@ static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86 > /* TODO: setting to 4 MIPI lanes always for now */ > dsi->lanes = 4; > dsi->format = MIPI_DSI_FMT_RGB888; > - dsi->mode_flags = MIPI_DSI_MODE_VIDEO; > + dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_NO_EOT_PACKET | > + MIPI_DSI_MODE_VIDEO_SYNC_PULSE; FWIW, I can confirm that on my board the screen still seems to light up after this change. ...so I'd be OK w/ Tested-by: Douglas Anderson <dianders@chromium.org> ...before giving a Reviewed-by I'd want a description that helps me understand it better. -Doug
Hello Doug, On 13/04/25 07:22, Doug Anderson wrote: > Hi, > > On Fri, Apr 11, 2025 at 2:23 AM Jayesh Choudhary <j-choudhary@ti.com> wrote: >> >> Enable NO_EOT and SYNC flags for DSI to use VIDEO_SYNC_PULSE_MODE >> with EOT disabled. > > Any chance you could add some details to this commit message? Your > subject says that these flags are "necessary", but people have been > using this driver successfully for many years now. Why did these flags > suddenly become necessary and why were things working before? > > I'm not saying that we shouldn't use these flags, just trying to > understand. I actually don't know a ton about these details in MIPI, > so it would help me :-). > Definitely. I will add more details for the commit message. For more context here, I was working with cadence dsi driver for TI SoCs. So to be more accurate, this is required for CDNS_DSI I observed other bridges like lt-9211, where I have seen such flags being set for dsi-controller by vendors. > >> Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com> >> --- >> drivers/gpu/drm/bridge/ti-sn65dsi86.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c >> index f72675766e01..8e9a7eb927da 100644 >> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c >> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c >> @@ -707,7 +707,8 @@ static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86 >> /* TODO: setting to 4 MIPI lanes always for now */ >> dsi->lanes = 4; >> dsi->format = MIPI_DSI_FMT_RGB888; >> - dsi->mode_flags = MIPI_DSI_MODE_VIDEO; >> + dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_NO_EOT_PACKET | >> + MIPI_DSI_MODE_VIDEO_SYNC_PULSE; > > FWIW, I can confirm that on my board the screen still seems to light > up after this change. ...so I'd be OK w/ > > Tested-by: Douglas Anderson <dianders@chromium.org> > > ...before giving a Reviewed-by I'd want a description that helps me > understand it better. > > -Doug
diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c index f72675766e01..8e9a7eb927da 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c @@ -707,7 +707,8 @@ static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86 /* TODO: setting to 4 MIPI lanes always for now */ dsi->lanes = 4; dsi->format = MIPI_DSI_FMT_RGB888; - dsi->mode_flags = MIPI_DSI_MODE_VIDEO; + dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_NO_EOT_PACKET | + MIPI_DSI_MODE_VIDEO_SYNC_PULSE; /* check if continuous dsi clock is required or not */ pm_runtime_get_sync(dev);
Enable NO_EOT and SYNC flags for DSI to use VIDEO_SYNC_PULSE_MODE with EOT disabled. Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com> --- drivers/gpu/drm/bridge/ti-sn65dsi86.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)