[RESEND PATCH v11 11/18] drm: exynos: dsi: Add atomic_get_input_bus_fmts

[Marek Vasut]

On 1/24/23 22:16, Jagan Teki wrote:
> On Wed, Jan 25, 2023 at 2:15 AM Marek Vasut <marex at denx.de> wrote:
>>
>> On 1/23/23 16:12, Jagan Teki wrote:
>>
>> [...]
>>
>>> +static bool exynos_dsi_pixel_output_fmt_supported(u32 fmt)
>>> +{
>>> +     int i;
>>
>> if (fmt == MEDIA_BUS_FMT_FIXED)
>>    return false;
>>
>>> +     for (i = 0; i < ARRAY_SIZE(exynos_dsi_pixel_output_fmts); i++) {
>>> +             if (exynos_dsi_pixel_output_fmts[i] == fmt)
>>> +                     return true;
>>> +     }
>>> +
>>> +     return false;
>>> +}
>>> +
>>> +static u32 *
>>> +exynos_dsi_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)
>>> +{
>>> +     u32 *input_fmts;
>>> +
>>> +     if (!exynos_dsi_pixel_output_fmt_supported(output_fmt))
>>> +             /*
>>> +              * Some bridge/display drivers are still not able to pass the
>>> +              * correct format, so handle those pipelines by falling back
>>> +              * to the default format till the supported formats finalized.
>>> +              */
>>> +             output_fmt = MEDIA_BUS_FMT_RGB888_1X24;
>>
>> You can move this ^ past the kmalloc() call, so in unlikely case the
>> kmalloc() fails, it would fail first.
> 
> I didn't get this point, what do we need to do if
> exynos_dsi_pixel_output_fmt_supported returns false?

{
	u32 *input_fmts;

	input_fmts = kmalloc(sizeof(*input_fmts), GFP_KERNEL);
	if (!input_fmts)
		return NULL;

	if (!exynos_dsi_pixel_output_fmt_supported(output_fmt))
		/* ... the comment ... */
		output_fmt = MEDIA_BUS_FMT_RGB888_1X24;

	input_fmts[0] = output_fmt;
	*num_input_fmts = 1;

	return input_fmts;
}