Re: [PATCH v2 2/2] drm/panel: simple: add NEC NL6448BC33-70C

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Hardware configuration mismatch causing WARN_ON stack traces and display failure.
--

commit ed55c8f29ffdce716c41311e39a5db4fabaf9549
Author: Steffen Trumtrar <s.trumtrar@pengutronix.de>

drm/panel: simple: add NEC NL6448BC33-70C

This commit adds support for the NEC NL6448BC33-70C 10.4" 640x480 LCD module
to the simple panel driver.

> diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
> index 236bd56208ccf..dca6cbc41bd9f 100644
> --- a/drivers/gpu/drm/panel/panel-simple.c
> +++ b/drivers/gpu/drm/panel/panel-simple.c
[ ... ]
> +static const struct panel_desc nec_nl6448bc33_70c = {
> +	.modes = &nec_nl6448bc33_70c_mode,
> +	.num_modes = 1,
> +	.bpc = 6,
> +	.size = {
> +		.width = 211,
> +		.height = 158,
> +	},
> +	.bus_format = MEDIA_BUS_FMT_RGB666_1X18,
> +	.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
> +	.connector_type = DRM_MODE_CONNECTOR_LVDS,

Are this bus_format and bus_flags compatible with an LVDS connector type?

In panel_simple_probe(), there are WARN_ON() checks that enforce strict
configuration rules for LVDS panels.

MEDIA_BUS_FMT_RGB666_1X18 is a parallel RGB (DPI) format, not an LVDS format
(like MEDIA_BUS_FMT_RGB666_1X7X3_SPWG). Because it is missing from the LVDS
format whitelist, it looks like this will trigger a warning during probe.

Similarly, DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE is not in the whitelist of
allowed LVDS flags, which guarantees the bus flag WARN_ON() will also trigger.

Could this mix of parallel RGB format settings with an LVDS connector type
cause hardware configuration issues or a corrupted display?

> +};

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260515-v7-1-topic-panel-simple-nl6448bc33-v2-0-74ab0baa1817@pengutronix.de?part=2