Re: [PATCH v8 1/1] [DRIVER] gpu: drm: add support for YHGCH ZX1000 soc chipset

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 29 Sep 2025, Chu Guangqing <chuguangqing@inspur.com> wrote:
> diff --git a/drivers/gpu/drm/yhgch/yhgch_drm_vdac.c b/drivers/gpu/drm/yhgch/yhgch_drm_vdac.c
> new file mode 100644
> index 000000000000..2e222af29f69
> --- /dev/null
> +++ b/drivers/gpu/drm/yhgch/yhgch_drm_vdac.c
> @@ -0,0 +1,134 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/io.h>
> +
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_edid.h>
> +#include <drm/drm_probe_helper.h>
> +#include <drm/drm_print.h>
> +#include <drm/drm_simple_kms_helper.h>
> +
> +#include "yhgch_drm_drv.h"
> +#include "yhgch_drm_regs.h"
> +
> +static int yhgch_connector_get_modes(struct drm_connector *connector)
> +{
> +	int count;
> +	const struct drm_edid *drm_edid;
> +
> +	drm_edid = drm_edid_read(connector);
> +	if (drm_edid) {
> +		drm_edid_connector_update(connector, drm_edid);

You're supposed to do drm_edid_connector_update() even for NULL edid to
reset it.

BR,
Jani.


> +		count =  drm_edid_connector_add_modes(connector);
> +		if (count)
> +			goto out;
> +	}
> +
> +	count = drm_add_modes_noedid(connector,
> +				     connector->dev->mode_config.max_width,
> +				     connector->dev->mode_config.max_height);
> +	drm_set_preferred_mode(connector, 1024, 768);
> +
> +out:
> +	drm_edid_free(drm_edid);
> +	return count;
> +}

-- 
Jani Nikula, Intel