Re: [PATCH v2 08/10] drm/ofdrm: Add CRTC state

Hi

Am 26.07.22 um 15:36 schrieb Javier Martinez Canillas:

On 7/20/22 16:27, Thomas Zimmermann wrote:

quoted

Add a dedicated CRTC state to ofdrm to later store information for
palette updates.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
  drivers/gpu/drm/tiny/ofdrm.c | 62 ++++++++++++++++++++++++++++++++++--
  

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

[...]

quoted

+static void ofdrm_crtc_reset(struct drm_crtc *crtc)
+{
+	struct ofdrm_crtc_state *ofdrm_crtc_state;
+
+	if (crtc->state) {
+		ofdrm_crtc_state_destroy(to_ofdrm_crtc_state(crtc->state));
+		crtc->state = NULL; /* must be set to NULL here */
+	}
+
+	ofdrm_crtc_state = kzalloc(sizeof(*ofdrm_crtc_state), GFP_KERNEL);
+	if (!ofdrm_crtc_state)
+		return;
+	__drm_atomic_helper_crtc_reset(crtc, &ofdrm_crtc_state->base);
+}
+

IMO this function is hard to read, I would instead write it as following:

static void ofdrm_crtc_reset(struct drm_crtc *crtc)
{
         struct ofdrm_crtc_state *ofdrm_crtc_state = kzalloc(sizeof(*ofdrm_crtc_state), GFP_KERNEL);

	if (!ofdrm_crtc_state)
		return;

         if (crtc->state) {
                 ofdrm_crtc_state_destroy(to_ofdrm_crtc_state(crtc->state));
		crtc->state = NULL; /* must be set to NULL here */
	}

         __drm_atomic_helper_crtc_reset(crtc, &ofdrm_crtc_state->base);
}

Also with that form I think that the crtc->state = NULL could just be dropped ?

I once had to add this line to a driver to make the DRM helpers work. 
But I cannot find any longer why. Maybe it's been resolved meanwhile.

Best regards
Thomas

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev