From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 9 Feb 2008 12:13:37 +0100 (CET) From: Michael Trimarchi In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Message-ID: <246938.91746.qm@domain.hid> Subject: Re: [Adeos-main] at91sam9260 List-Id: General discussion about Adeos List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Bosko Radivojevic , Gilles Chanteperdrix Cc: david-b@domain.hid, adeos-main@gna.org Hi, > Thanks. Actually, I have simillar problems (buffer > overrun) when working > with serial port (at91sam9260-ek based board). But, > I haven't inspected the > problem more than that. I'll do that next week. > > On Feb 8, 2008 8:36 PM, Gilles Chanteperdrix > > wrote: > > > > > I received a mail from Michael recently telling me > that he observes the > > same behaviour with the PREEMPT_RT patch, so the > I-pipe patch is > > probably out of cause. He now suspects a hardware > issue (one serial port > > pin seems to be shared with another peripheral, as > I think I understood). > > > > > I finish my investigation, and I think that depens only in some overhead. In linux is present using hrtimer and doesn't depends on NO_HZ options. If some hrtimer is executed with the interrupts disabled and the serial must receive a single char, you receive and overrun. I suppose that the NO_HZ option can be a solution (less interrupt) but an the end, doesn't change. The dma patch on serial device resolve the problem. I think that for adeos is the same. I try to investigate, how long is the max blocking time in hrtimer interrupt. Using TC timer is ok. David and Gilles, you are right but I want to know how in linux-rt and adeos, I can reduce the latency to support this interrupts frquency. Regards Michael ___________________________________ L'email della prossima generazione? Puoi averla con la nuova Yahoo! Mail: http://it.docs.yahoo.com/nowyoucan.html