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    SubjectRe: [PATCH -mm v4 6/9] atmel_serial: Split the interrupt handler
    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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