| Message ID | 20180618102806.15650-4-heiko@sntech.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Heiko, On 06/18/2018 12:28 PM, Heiko Stuebner wrote: > When the panel-driver is build as a module it currently fails hard as the > panel cannot be probed directly: > > dw_mipi_dsi_bind() > __dw_mipi_dsi_probe() > creates dsi bus > creates panel device > triggers panel module load > panel not probed (module not loaded or panel probe slow) > drm_bridge_attach > fails with -EINVAL due to empty panel_bridge > > So emit a -EPROBE_DEFER in that case to give the driver another > chance at getting the display later. > > Signed-off-by: Heiko Stuebner <heiko@sntech.de> > --- > drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > index bb4aeca5c0f9..bd503f000ed5 100644 > --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > @@ -835,6 +835,9 @@ static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge) > return -ENODEV; > } > > + if (!dsi->panel_bridge) > + return -EPROBE_DEFER; > + Thank you for your patch, Reviewed-by: Philippe Cornu <philippe.cornu@st.com> Tested-by: Philippe Cornu <philippe.cornu@st.com> Philippe :-) > /* Set the encoder type as caller does not know it */ > bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI; > >
On 18.06.2018 12:28, Heiko Stuebner wrote: > When the panel-driver is build as a module it currently fails hard as the > panel cannot be probed directly: > > dw_mipi_dsi_bind() > __dw_mipi_dsi_probe() > creates dsi bus > creates panel device > triggers panel module load > panel not probed (module not loaded or panel probe slow) > drm_bridge_attach > fails with -EINVAL due to empty panel_bridge > > So emit a -EPROBE_DEFER in that case to give the driver another > chance at getting the display later. Thats odd (at least for me), if the resource (panel in this case) is not present, bridge should not be attached (drm_bridge_attach should not be called). Ie __dw_mipi_dsi_probe should rather look for the panel and defer if not found. Resource gathering is the task of probe. drm_bridge_attach can be called after probe and it would be difficult for the caller to react properly for -EPROBE_DEFER error. Regards Andrzej > > Signed-off-by: Heiko Stuebner <heiko@sntech.de> > --- > drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > index bb4aeca5c0f9..bd503f000ed5 100644 > --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > @@ -835,6 +835,9 @@ static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge) > return -ENODEV; > } > > + if (!dsi->panel_bridge) > + return -EPROBE_DEFER; > + > /* Set the encoder type as caller does not know it */ > bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI; >
Am Dienstag, 3. Juli 2018, 14:42:49 CEST schrieb Andrzej Hajda: > On 18.06.2018 12:28, Heiko Stuebner wrote: > > When the panel-driver is build as a module it currently fails hard as the > > panel cannot be probed directly: > > > > dw_mipi_dsi_bind() > > __dw_mipi_dsi_probe() > > creates dsi bus > > creates panel device > > triggers panel module load > > panel not probed (module not loaded or panel probe slow) > > drm_bridge_attach > > fails with -EINVAL due to empty panel_bridge > > > > So emit a -EPROBE_DEFER in that case to give the driver another > > chance at getting the display later. > > Thats odd (at least for me), if the resource (panel in this case) is not > present, bridge should not be attached (drm_bridge_attach should not be > called). Ie __dw_mipi_dsi_probe should rather look for the panel and > defer if not found. Resource gathering is the task of probe. > drm_bridge_attach can be called after probe and it would be difficult > for the caller to react properly for -EPROBE_DEFER error. I think one of the problems comes from the fact that the panel only gets probed (and even the panel-device created) after the dsi host bus gets created in __dw_mipi_dsi_probe. In hindsight, I think this is more of a concurrency issue between the panel probing and calling dsi-attach and the dsi-controller looking for the panel vs. panel-bridge. So when I'm using drm_of_find_panel_or_bridge() as indicator of the panel being, it probably makes things racy. I'll try to find a better solution for the issue. Heiko
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c index bb4aeca5c0f9..bd503f000ed5 100644 --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c @@ -835,6 +835,9 @@ static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge) return -ENODEV; } + if (!dsi->panel_bridge) + return -EPROBE_DEFER; + /* Set the encoder type as caller does not know it */ bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI;
When the panel-driver is build as a module it currently fails hard as the panel cannot be probed directly: dw_mipi_dsi_bind() __dw_mipi_dsi_probe() creates dsi bus creates panel device triggers panel module load panel not probed (module not loaded or panel probe slow) drm_bridge_attach fails with -EINVAL due to empty panel_bridge So emit a -EPROBE_DEFER in that case to give the driver another chance at getting the display later. Signed-off-by: Heiko Stuebner <heiko@sntech.de> --- drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 3 +++ 1 file changed, 3 insertions(+)