On Thu, 04 Jun 2026 16:52:19 +0800, Damon Ding <[email protected]> wrote:
Hello Damon, > > diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > index 7a85774aaac1..e120ef3320c1 100644 > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > @@ -1261,8 +1262,11 @@ static int analogix_dp_dt_parse_pdata(struct > analogix_dp_device *dp) > */ > of_property_read_u32(dp_node, "samsung,link-rate", > &video_info->max_link_rate); > - of_property_read_u32(dp_node, "samsung,lane-count", > - &video_info->max_lane_count); > + ret = of_property_read_u32(dp_node, "samsung,lane-count", > + &video_info->max_lane_count); > + if (ret || > !drm_dp_lane_count_is_valid(video_info->max_lane_count)) > + return dev_err_probe(dp->dev, ret ? ret : -EINVAL, > + "failed to parse > samsung,lane-count\n"); I think this report by sashiko makes sense: > [email protected] <[email protected]>: > > [Severity: High] > Does this make the optional and deprecated samsung,lane-count property a > strict requirement? > > If samsung,lane-count is absent from the device tree, of_property_read_u32() > returns -EINVAL. This causes the condition to evaluate to true, aborting the > probe with an error. > > According to the device tree bindings > (Documentation/devicetree/bindings/display/samsung/samsung,exynos5-dp.yaml), > this property is marked as deprecated and explicitly optional because the > lane count can be read from the monitor. Does this patch break compatibility > with device trees that rightfully omit this deprecated property? (via: https://patch.msgid.link/[email protected]) Can you comment on this? Luca -- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
