Messages in this thread | | | Subject | Re: [PATCH for 5.6 v2] tty: serial: tegra: Handle RX transfer in PIO mode if DMA wasn't started | From | Jiri Slaby <> | Date | Mon, 17 Feb 2020 08:37:06 +0100 |
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On 09. 02. 20, 17:44, Dmitry Osipenko wrote: > It is possible to get an instant RX timeout or end-of-transfer interrupt > before RX DMA was started, if transaction is less than 16 bytes. Transfer > should be handled in PIO mode in this case because DMA can't handle it. > This patch brings back the original behaviour of the driver that was > changed by accident by a previous commit, it fixes occasional Bluetooth HW > initialization failures which I started to notice recently. > > Fixes: d5e3fadb7012 ("tty: serial: tegra: Activate RX DMA transfer by request") > Signed-off-by: Dmitry Osipenko <digetx@gmail.com> > --- > > Changelog: > > v2: - Corrected commit's title by adding the accidentally missed "tegra: " > to the prefix. > > drivers/tty/serial/serial-tegra.c | 35 ++++++++++++++----------------- > 1 file changed, 16 insertions(+), 19 deletions(-) > > diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c > index 33034b852a51..8de8bac9c6c7 100644 > --- a/drivers/tty/serial/serial-tegra.c > +++ b/drivers/tty/serial/serial-tegra.c > @@ -692,11 +692,22 @@ static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup, > count, DMA_TO_DEVICE); > } > > +static void do_handle_rx_pio(struct tegra_uart_port *tup) > +{ > + struct tty_struct *tty = tty_port_tty_get(&tup->uport.state->port); > + struct tty_port *port = &tup->uport.state->port; > + > + tegra_uart_handle_rx_pio(tup, port); > + if (tty) {
What's the tty good for here, actually?
> + tty_flip_buffer_push(port); > + tty_kref_put(tty); > + } > +}
thanks, -- js suse labs
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