Re: [PATCH v11 2/3] drm/bridge: imx: Add i.MX93 parallel display format configuration support

[Frank Li <Frank.li@nxp.com>]

On Tue, Mar 03, 2026 at 10:22:02PM +0100, Marco Felsch wrote:
> On 26-03-03, Frank Li wrote:
> > From: Frank Li (AI-BOT) <frank.li@nxp.com>
> >
> > AI bot review and may be useless.
>
> Hi Frank,
>
> albeit I'm very open to new technology, I would appreciate it if your
> AI-BOT is used internally first till you're convinced that it reports
> real issues instead of false-positives.
>
> Regards,
>   Marco
>
> > > +static u32 *
> > > +imx93_pdfc_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
> > > +					    struct drm_bridge_state *bridge_state,
> > > +					    struct drm_crtc_state *crtc_state,
> > > +					    struct drm_connector_state *conn_state,
> > > +					    u32 output_fmt,
> > > +					    unsigned int *num_input_fmts)
> > > +{
> > > +	struct imx93_pdfc *pdfc = bridge_to_imx93_pdfc(bridge);
> > > +	u32 *input_fmts;
> > > +
> > > +	*num_input_fmts = 0;
> > > +
> > > +	input_fmts = kmalloc_obj(*input_fmts);
> > > +	if (!input_fmts)
> > > +		return NULL;
> >

> +     input_fmts = kmalloc_obj(*input_fmts);

AI:

Actually, this looks incorrect. kmalloc_obj() allocates based on the type
of the pointer argument. Here you're passing *input_fmts (a u32), not
input_fmts (a u32 *). Should be:

+       input_fmts = kmalloc_array(*num_input_fmts, sizeof(*input_fmts),
+                                  GFP_KERNEL);

suppose you use kmalloc_objs()

Frank

> > Missing kfree(input_fmts) in error path if the switch statement
> > or subsequent logic fails. Consider allocating a fixed-size array
> > or using devm_kzalloc() instead.
> >
> > > +	*num_input_fmts = 1;
> > > +
> > > +	if (!imx93_pdfc_bus_output_fmt_supported(output_fmt)) {
> > > +		dev_dbg(pdfc->dev, "No valid output bus-fmt detected, fallback to MEDIA_BUS_FMT_RGB888_1X24\n");
> >
> > Line exceeds 80 characters (97 chars). Break into two lines.
> >
> > > +		input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
> > > +		return input_fmts;
> > > +	}
> > > +
> > > +	switch (output_fmt) {
> > > +	case MEDIA_BUS_FMT_RGB888_1X24:
> > > +	case MEDIA_BUS_FMT_RGB565_1X16:
> > > +		input_fmts[0] = output_fmt;
> > > +		break;
> > > +	case MEDIA_BUS_FMT_RGB666_1X18:
> > > +	case MEDIA_BUS_FMT_FIXED:
> > > +		input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
> > > +		break;
> > > +	}
> >
> > Switch statement lacks default case. Add default case to handle
> > unexpected format values explicitly.
> >
> > > +static int imx93_pdfc_bridge_atomic_enable(struct drm_bridge *bridge,
> > > +					    struct drm_atomic_state *state)
> > > +{
> > > +	struct imx93_pdfc *pdfc = bridge_to_imx93_pdfc(bridge);
> > > +	const struct drm_bridge_state *bridge_state;
> > > +	unsigned int mask = PARALLEL_DISP_FORMAT;
> > > +	unsigned int val;
> > > +
> > > +	bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
> > > +
> > > +	switch (bridge_state->output_bus_cfg.format) {
> > > +	case MEDIA_BUS_FMT_RGB888_1X24:
> > > +	case MEDIA_BUS_FMT_FIXED:
> > > +		val = FORMAT_RGB888_TO_RGB888;
> > > +		if (pdfc->phy_bus_width == 18) {
> > > +			/*
> > > +			 * Can be valid if physical bus limitation exists,
> > > +			 * therefore use dev_dbg().
> > > +			 */
> > > +			dev_dbg(pdfc->dev, "Truncate two LSBs from each color\n");
> > > +			val = FORMAT_RGB888_TO_RGB666;
> > > +		}
> > > +		break;
> > > +	case MEDIA_BUS_FMT_RGB666_1X18:
> > > +		val = FORMAT_RGB888_TO_RGB666;
> > > +
> >
>
> --
> #gernperDu
> #CallMeByMyFirstName
>
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