From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Holler Date: Tue, 29 Jan 2013 20:56:47 +0000 Subject: Re: [PATCH 2/3 v2] fb: udlfb: fix hang at disconnect Message-Id: <5108378F.80003@ahsoftware.de> List-Id: References: <50F2A310.5010006@ahsoftware.de> <1359139768-32294-1-git-send-email-holler@ahsoftware.de> <1359139768-32294-2-git-send-email-holler@ahsoftware.de> <20130128162238.7fba92fe.akpm@linux-foundation.org> <51071E21.9030008@ahsoftware.de> <5107A5ED.7020009@ahsoftware.de> <5107AE4F.9000809@ahsoftware.de> <5107F014.4030704@ahsoftware.de> <5108329E.2050802@ahsoftware.de> In-Reply-To: <5108329E.2050802@ahsoftware.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org, Florian Tobias Schandinat , Bernie Thompson , Steve Glendinning , stable@vger.kernel.org Am 29.01.2013 21:35, schrieb Alexander Holler: > > So, if the above down_timeout_killable() is only down_interruptible(), > as in kernel 3.7.5, the box would not shutdown afterwards, because on > shutdown no signal would be send to that kernel-thread which called > dlfb_free_urb_list(). > > A last note: dlfb_usb_disconnect() (thus dlfb_free_urb_list()) isn't > called on shutdown if the device would still be connected. So the > problem only might happen, if the screen will be disconnected before > shutdown (and an urb gets missed). So the subject of my patch is > correct. ;) > > Hmm, wrong, sorry, I still have something to add: As no signal arrives at all, v1 of that patch is enough and the implementation of down_timeout_killable() isn't necessary at all. If there is a chance that the patch would be Acked-by by someone, I would made a v3, replacing + ret = down_timeout(&dev->urbs.limit_sem, GET_URB_TIMEOUT); in v1 with + ret = down_timeout(&dev->urbs.limit_sem, FREE_URB_TIMEOUT); as this seems to be what it should be. Regards, Alexander