Messages in this thread | | | Date | Thu, 14 Feb 2008 08:30:47 +0100 | From | michael <> | Subject | Re: [PATCH -mm v4 6/9] atmel_serial: Split the interrupt handler |
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Hi, Remy Bohmer wrote: > Hello All, > > >> All works now for me with preempt-rt. The problem is using hrtimer. >> I think that hrtimer are executed with interrupts disabled so, if >> this happen when I must receive a char, i have an overrun. >> > > No, they share the same interrupt line... > I think that the hrtimer use and other interrupt line. The AT91SAM9260_ID_TC2. > So, while the timer interrupt handler is running, the serial handler > has to wait until the timer interrupt handler has finished. > Notice that the HRT interrupt handler is quite heavy and takes a long > time to complete. > The problem is the heavy of HRT interrupt handler of course. > And, as I already mentioned, related to the 1 byte FIFO and a > interrupt latency of about 85us (without HRT), it is logical that you > can get an overrun at the higher serial speeds... (>=115200bps) > > I don't have the same problem without the hrtimer, I suppose the the timer latency is not so heavy. >> The only solution was the dma support to serial device. >> > > Or, use flow control? > > > Yes :)
Michael
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