From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Witzel Subject: Re: [Xenomai-help] Re: RTDM driver questions Date: Sun, 21 May 2006 21:19:53 +0000 References: <050720061514.21865.445E0ED2000D33230000556922058863609C0E0301089BD2040A969B0799@domain.hid> <200605072202.22555.witzel.thomas@domain.hid> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200605212119.53330.witzel.thomas@domain.hid> Reply-To: witzel.thomas@domain.hid List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: xenomai@xenomai.org I have that now, but I'm not really sure how to synchronize the user space application with the driver, since the driver has of course only a limited buffer. Practically now I have a 512 sample buffer in the driver that I use as a double buffer and I copy blocks of 256 to the user on read. Isn't there a way to have a FIFO between driver and user application and is there an example somewhere, where I can see how this is done properly ? Independently of that, if the user space application dies, how can I remove the driver then ? Thank you, Thomas On Sunday 07 May 2006 22:21, Bernhard Walle wrote: > Hi Thomas, > > Thomas Witzel [2006-05-07]: > > > Generally spoken, mmap can make sense if you have a significant amount > > > of data to transfer, not "just" a few kbyte/s. RTDM has the elementary > > > support for such device interfaces now, and this has already been used > > > for a frame-grabbing driver. > > > > What would be the proper procedure for just a few kbytes ? I expect less > > than 500 kB./second in my application. > > Simply read() / write() ? > > > Regards, > Bernhard