Hi Am 25.01.23 um 22:03 schrieb Sam Ravnborg:
Hi Thomas, On Wed, Jan 25, 2023 at 09:04:09PM +0100, Thomas Zimmermann wrote:Initialize the fb-helper structure immediately after its allocation in drm_fbdev_generic_setup(). That will make it easier to fill it with driver-specific values, such as the preferred BPP. Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx> --- drivers/gpu/drm/drm_fbdev_generic.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/drm_fbdev_generic.c b/drivers/gpu/drm/drm_fbdev_generic.c index 135d58b8007b..63f66325a8a5 100644 --- a/drivers/gpu/drm/drm_fbdev_generic.c +++ b/drivers/gpu/drm/drm_fbdev_generic.c @@ -385,8 +385,6 @@ static int drm_fbdev_client_hotplug(struct drm_client_dev *client) if (dev->fb_helper) return drm_fb_helper_hotplug_event(dev->fb_helper);- drm_fb_helper_prepare(dev, fb_helper, &drm_fb_helper_generic_funcs);- ret = drm_fb_helper_init(dev, fb_helper); if (ret) goto err;From the documentation: The drm_fb_helper_prepare() helper must be called first to initialize the minimum required to make hotplug detection work. ... To finish up the fbdev helper initialization, the drm_fb_helper_init() function is called. So this change do not follow the documentation as drm_fb_helper_init() is now called before drm_fb_helper_prepare()
No, we now call drm_fb_helper_prepare() from within drm_fbdev_generic_setup(), right after allocating the fb_helper. drm_fb_helper_init() will only be called after the client received a hot-plug event.
I did not follow all the code - but my gut feeling is that the documentation is right.
The docs are of low quality. The _prepare() helper is the actual init function and _init() only sets the fb_helper in the device instance.
Best regards Thomas
Sam@@ -456,12 +454,12 @@ void drm_fbdev_generic_setup(struct drm_device *dev, fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL); if (!fb_helper) return; + drm_fb_helper_prepare(dev, fb_helper, &drm_fb_helper_generic_funcs);ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_client_funcs);if (ret) { - kfree(fb_helper); drm_err(dev, "Failed to register client: %d\n", ret); - return; + goto err_drm_client_init; }/*@@ -484,5 +482,12 @@ void drm_fbdev_generic_setup(struct drm_device *dev, drm_dbg_kms(dev, "client hotplug ret=%d\n", ret);drm_client_register(&fb_helper->client);+ + return; + +err_drm_client_init: + drm_fb_helper_unprepare(fb_helper); + kfree(fb_helper); + return; } EXPORT_SYMBOL(drm_fbdev_generic_setup); -- 2.39.0
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Ivo Totev
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