From: Javier Martinez Canillas <javierm@redhat.com> To: Thomas Zimmermann <tzimmermann@suse.de>, zackr@vmware.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, airlied@linux.ie, daniel@ffwll.ch, deller@gmx.de, hdegoede@redhat.com Cc: linux-fbdev@vger.kernel.org, stable@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH 1/5] fbdev: Hot-unplug firmware fb devices on forced removal Date: Mon, 24 Jan 2022 15:31:13 +0100 [thread overview] Message-ID: <410efcd1-c104-313b-aee8-950c4f499405@redhat.com> (raw) In-Reply-To: <77e52472-4af7-c03f-f6e4-45ec820f2778@suse.de> On 1/24/22 15:19, Thomas Zimmermann wrote: [snip] >>> + if (dev_is_platform(dev)) { >> >> In do_register_framebuffer() creating the fb%d is not a fatal error. It would >> be safer to do if (!IS_ERR_OR_NULL(dev) && dev_is_platform(dev)) instead here. >> >> https://elixir.bootlin.com/linux/latest/source/drivers/video/fbdev/core/fbmem.c#L1605 > > 'dev' here refers to 'fb_info->device', which is the underlying device > created by the sysfb code. fb_info->dev is something different. > oh, indeed. I conflated the two. Maybe the local variable could be renamed to 'device' just to avoid confusion ? [snip] >> I'm not sure to follow the logic here. The forced_out bool is set when the >> platform device is unregistered in do_remove_conflicting_framebuffers(), >> but shouldn't the struct platform_driver .remove callback be executed even >> in this case ? >> >> That is, the platform_device_unregister() will trigger the call to the >> .remove callback that in turn will call unregister_framebuffer(). >> >> Shouldn't we always hold the mutex when calling do_unregister_framebuffer() ? > > Doing the hot-unplug will end up in unregister_framebuffer(), but we > already hold the lock from the do_remove_conflicting_framebuffer() code. > Yes, I realized that just after sending the first email. Sorry for the noise. Best regards, -- Javier Martinez Canillas Linux Engineering Red Hat
WARNING: multiple messages have this Message-ID (diff)
From: Javier Martinez Canillas <javierm@redhat.com> To: Thomas Zimmermann <tzimmermann@suse.de>, zackr@vmware.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, airlied@linux.ie, daniel@ffwll.ch, deller@gmx.de, hdegoede@redhat.com Cc: linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, stable@vger.kernel.org Subject: Re: [PATCH 1/5] fbdev: Hot-unplug firmware fb devices on forced removal Date: Mon, 24 Jan 2022 15:31:13 +0100 [thread overview] Message-ID: <410efcd1-c104-313b-aee8-950c4f499405@redhat.com> (raw) In-Reply-To: <77e52472-4af7-c03f-f6e4-45ec820f2778@suse.de> On 1/24/22 15:19, Thomas Zimmermann wrote: [snip] >>> + if (dev_is_platform(dev)) { >> >> In do_register_framebuffer() creating the fb%d is not a fatal error. It would >> be safer to do if (!IS_ERR_OR_NULL(dev) && dev_is_platform(dev)) instead here. >> >> https://elixir.bootlin.com/linux/latest/source/drivers/video/fbdev/core/fbmem.c#L1605 > > 'dev' here refers to 'fb_info->device', which is the underlying device > created by the sysfb code. fb_info->dev is something different. > oh, indeed. I conflated the two. Maybe the local variable could be renamed to 'device' just to avoid confusion ? [snip] >> I'm not sure to follow the logic here. The forced_out bool is set when the >> platform device is unregistered in do_remove_conflicting_framebuffers(), >> but shouldn't the struct platform_driver .remove callback be executed even >> in this case ? >> >> That is, the platform_device_unregister() will trigger the call to the >> .remove callback that in turn will call unregister_framebuffer(). >> >> Shouldn't we always hold the mutex when calling do_unregister_framebuffer() ? > > Doing the hot-unplug will end up in unregister_framebuffer(), but we > already hold the lock from the do_remove_conflicting_framebuffer() code. > Yes, I realized that just after sending the first email. Sorry for the noise. Best regards, -- Javier Martinez Canillas Linux Engineering Red Hat
next prev parent reply other threads:[~2022-01-24 14:31 UTC|newest] Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-24 12:36 [PATCH 0/5] sysfb: Fix memory-region management Thomas Zimmermann 2022-01-24 12:36 ` Thomas Zimmermann 2022-01-24 12:36 ` [PATCH 1/5] fbdev: Hot-unplug firmware fb devices on forced removal Thomas Zimmermann 2022-01-24 12:36 ` Thomas Zimmermann 2022-01-24 13:52 ` Javier Martinez Canillas 2022-01-24 13:52 ` Javier Martinez Canillas 2022-01-24 13:56 ` Javier Martinez Canillas 2022-01-24 13:56 ` Javier Martinez Canillas 2022-01-24 14:19 ` Thomas Zimmermann 2022-01-24 14:19 ` Thomas Zimmermann 2022-01-24 14:31 ` Javier Martinez Canillas [this message] 2022-01-24 14:31 ` Javier Martinez Canillas 2022-01-24 15:59 ` Zack Rusin 2022-01-24 15:59 ` Zack Rusin 2022-01-24 12:36 ` [PATCH 2/5] drivers/firmware: Don't mark as busy the simple-framebuffer IO resource Thomas Zimmermann 2022-01-24 12:36 ` Thomas Zimmermann 2022-01-24 15:59 ` Zack Rusin 2022-01-24 15:59 ` Zack Rusin 2022-01-24 12:36 ` [PATCH 3/5] drm/simpledrm: Request memory region in driver Thomas Zimmermann 2022-01-24 12:36 ` Thomas Zimmermann 2022-01-24 14:00 ` Javier Martinez Canillas 2022-01-24 14:00 ` Javier Martinez Canillas 2022-01-24 14:23 ` Jocelyn Falempe 2022-01-25 8:31 ` Thomas Zimmermann 2022-01-24 12:36 ` [PATCH 4/5] fbdev/simplefb: " Thomas Zimmermann 2022-01-24 12:36 ` Thomas Zimmermann 2022-01-24 14:24 ` Javier Martinez Canillas 2022-01-24 14:24 ` Javier Martinez Canillas 2022-01-24 12:36 ` [PATCH 5/5] drm: Add TODO item for requesting memory regions Thomas Zimmermann 2022-01-24 12:36 ` Thomas Zimmermann 2022-01-24 14:25 ` Javier Martinez Canillas 2022-01-24 14:25 ` Javier Martinez Canillas 2022-01-25 9:12 [PATCH 0/5] sysfb: Fix memory-region management Thomas Zimmermann 2022-01-25 9:12 ` [PATCH 1/5] fbdev: Hot-unplug firmware fb devices on forced removal Thomas Zimmermann 2022-01-25 9:12 ` Thomas Zimmermann
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