Messages in this thread | | | From | Linus Walleij <> | Date | Thu, 22 Apr 2021 02:18:18 +0200 | Subject | Re: [PATCH 05/26] serial: amba-pl011: drop low-latency workaround |
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On Wed, Apr 21, 2021 at 11:55 AM Johan Hovold <johan@kernel.org> wrote:
> Commit ead76f329f77 ("ARM: 6763/1: pl011: add optional RX DMA to PL011 > v2") added RX DMA support and also reproduced the workaround for the > infamous low_latency behaviour of tty_flip_buffer_push() by dropping and > reacquiring the port lock during receive processing. > > Since commit a9c3f68f3cd8 ("tty: Fix low_latency BUG"), > tty_flip_buffer_push() always schedules a work item to push data to the > line discipline and there's no need to keep any low_latency hacks around. > > Note that the port lock is also dropped in the PIO path > (see pl011_rx_chars), but it is not clear whether this is still needed > by the DMA code added by the aforementioned commit. > > Cc: Linus Walleij <linus.walleij@linaro.org> > Cc: Russell King <linux@armlinux.org.uk> > Signed-off-by: Johan Hovold <johan@kernel.org>
Looks like the right thing to do to me! Thanks for digging this out. Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Yours, Linus Walleij
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