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    SubjectRe: [PATCH 1/3] i2c: bcm2835: Fix hang for writing messages larger than 16 bytes
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    Noralf Trønnes <noralf@tronnes.org> writes:

    > Writing messages larger than the FIFO size results in a hang, rendering
    > the machine unusable. This is because the RXD status flag is set on the
    > first interrupt which results in bcm2835_drain_rxfifo() stealing bytes
    > from the buffer. The controller continues to trigger interrupts waiting
    > for the missing bytes, but bcm2835_fill_txfifo() has none to give.
    > In this situation wait_for_completion_timeout() apparently is unable to
    > stop the madness.
    >
    > The BCM2835 ARM Peripherals datasheet has this to say about the flags:
    > TXD: is set when the FIFO has space for at least one byte of data.
    > RXD: is set when the FIFO contains at least one byte of data.
    > TXW: is set during a write transfer and the FIFO is less than full.
    > RXR: is set during a read transfer and the FIFO is or more full.
    >
    > Implementing the logic from the downstream i2c-bcm2708 driver solved
    > the hang problem.
    >
    > Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

    Patches 1, 3 are:

    Reviewed-by: Eric Anholt <eric@anholt.net>

    For patch 2 I followed some of it, but couldn't quite say it's a review.
    I trust your testing, and that the path has had a lot more testing in
    the downstream tree, so it's:

    Acked-by: Eric Anholt <eric@anholt.net>

    Thanks!
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