From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hedwin Koning Date: Tue, 17 Nov 2009 02:41:09 +0100 Subject: [Buildroot] UDEV Card reader In-Reply-To: References: Message-ID: <4B01FF35.5080902@gmail.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Pablo Trujillo wrote: > Hi everyone this is my first post I don't know if is correct to ask > this here, My natural idiom is not English so sorry for mistakes: > > I was working with the buildroot around one year and I'm very glad > for all its benefits to make a real small custom system. > > Im trying with the udev system (no the mdev that come with busybox). > But the thing is that i don't understand why no work with card readers > I was searching in google and I found this: > > http://shallowsky.com/blog/linux/udev-cardreaders-update.html > > I try that but nothing happen, I don't know why. > > if I put the compact flash and later I insert the reader , the system > detect the card, but if I plug first the reader and after I put the > CF, nothing happen, I mean the plug & unplug event seem not to work. > > If anyone can help me > > by the way :X86 architecture. > > regards > _______________________________________________ > buildroot mailing list > buildroot at busybox.net > http://lists.busybox.net/mailman/listinfo/buildroot > > Hi The problem with cardreaders is is that when memory cards are inserted after the cardreader itself is inserted no events are sent to the kernel by the cardreader. To solve this you need to run a background process that monitors insertion and removals of memory cards. The background process repeatingly tries to open the devices of the cardreader. Once it does the normal events (add, remove) are sent by the kernel which can be handled by either udev of mdev. In linux HAL takes care of this. If you try it on a linux machine you can see the background processes using ps. Once you have the process names you can easily find them back in the HAL source code. Hedwin Koning.