From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262788AbTJPKRO (ORCPT ); Thu, 16 Oct 2003 06:17:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262792AbTJPKRO (ORCPT ); Thu, 16 Oct 2003 06:17:14 -0400 Received: from shark.pro-futura.com ([161.58.178.219]:17596 "EHLO shark.pro-futura.com") by vger.kernel.org with ESMTP id S262788AbTJPKRN (ORCPT ); Thu, 16 Oct 2003 06:17:13 -0400 From: "Tvrtko A. =?iso-8859-2?q?Ur=B9ulin?=" To: "Suresh Subramanian" , linux-kernel@vger.kernel.org Subject: Re: Problems in Device Driver Development Date: Thu, 16 Oct 2003 12:19:23 +0200 User-Agent: KMail/1.5.1 References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200310161219.23803.tvrtko@croadria.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > 1. We are not able to use copy_to_user() a chunk of memory from 'write' > function of the device driver. The pointer in the user space is passed to > the kernel space through the 'ioctl' function of the device driver. I am sure you get some return value from that function wich tells you what the problem is... > 2. We are not able to send a signal using kill_fasync() from within a > kernel thread, to an user space process. The problem we face when we do > this is that we get an OOPS message. I tried hard to decode this message, > but in vain. So we came to the conclusion that i cannot send a signal from > within the kernel thread using kill_fasync to a process that is running in > the user space. Am i right in my conclusion, if not what should i do to > make it possible. > > 3. Similar to problem numbered 2, we face same problems in doing with > 'tasklets'. kill_fasync() works just fine if used properly. Try to find Linux Device Drivers 2nd edition online book, it can explain this basic question to you.