Hi Am 13.04.22 um 18:05 schrieb Daniel Vetter:
On Wed, Apr 13, 2022 at 12:50:50PM +0200, Javier Martinez Canillas wrote:On 4/13/22 11:24, Thomas Zimmermann wrote:A workaround makes fbdev hot-unplugging work for framebuffers without device. The only user for this feature was offb. As each OF framebuffer now has an associated platform device, the workaround is no longer needed. Remove it. Effectively reverts commit 0f525289ff0d ("fbdev: Fix unregistering of framebuffers without device"). Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> --- drivers/video/fbdev/core/fbmem.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index bc6ed750e915..bdd00d381bbc 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1579,14 +1579,7 @@ static void do_remove_conflicting_framebuffers(struct apertures_struct *a, * If it's not a platform device, at least print a warning. A * fix would add code to remove the device from the system. */ - if (!device) { - /* TODO: Represent each OF framebuffer as its own - * device in the device hierarchy. For now, offb - * doesn't have such a device, so unregister the - * framebuffer as before without warning. - */ - do_unregister_framebuffer(registered_fb[i]);Maybe we could still keep this for a couple of releases but with a big warning that's not supported in case there are out-of-tree drivers out there that still do this ? Or at least a warning if the do_unregister_framebuffer() call is removed.Yeah dying while holding console_lock isn't fun, and not having a WARN_ON + bail-out code pretty much forces bug reporters to do a bisect here to give us something more than "machine dies at boot with no messages". I'd just outright keep the WARN_ON here for 1-2 years even to really make sure we got all the bug reports, since often these older machines only update onto LTS releases.
If that's what the consent is, I'll go with it.I'm just not sure if we talk about the same problem. offb didn't have a platform device, so we recently added this workaround with 'if (!device)'. All the other fbdev drivers have a platform device; and anything else that could fail is out-of-tree. We don't really care about those AFAIK.
With offb converted, we could practically remove all of the checks here and call platform_device_unregister() unconditionally.
Best regards Thomas
And it needs to be a WARN_ON + bail out since BUG_ON is as bad as just oopsing. -DanielRegardless of what you chose to do, the patch looks good to me. Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx> -- Best regards, Javier Martinez Canillas Linux Engineering Red Hat
-- 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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