From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Date: Wed, 05 Mar 2008 23:46:53 +0000 Subject: Re: Behaviour of device_register Message-Id: <20080305234653.GA5904@kroah.com> List-Id: References: <8b67d60803051525g3aca775dmc14d1c2450b34168@mail.gmail.com> In-Reply-To: <8b67d60803051525g3aca775dmc14d1c2450b34168@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Adrian McMenamin Cc: LKML , linux-sh On Wed, Mar 05, 2008 at 11:25:48PM +0000, Adrian McMenamin wrote: > The observed behaviour for me is that it appears to be blocking the > vblank interrupt on my box (or more accurately stopping the workqueue > that the interrupt handler calls from running). And without the vblank > my bus won't process dma and so therefore the attempt to register the > device in question fails. > > But I can see no reason from a glance over the code why that (vblanks > being blocked) would be the case - have I missed something and the > vblanks will be blocked, or should I be looking elsewhere for the root > cause of this problem? device_register(), on it's own, does not touch any hardware, nor prevent anything else in the kernel from happening. So I think you need to look elsewhere, like into the bus that is doing the device_register() call :) good luck, greg k-h