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| author | Johan Hovold <johan@kernel.org> | 2021-04-12 11:38:13 +0200 |
|---|---|---|
| committer | Johan Hovold <johan@kernel.org> | 2021-04-13 18:19:32 +0200 |
| commit | 4b8e07951ff53e702bd5d6d21450b17152d124d7 (patch) | |
| tree | fc53ab84be2861b5f3e7dde4b593e23d43be43dc /drivers/usb/serial/io_ti.c | |
| parent | USB: serial: f81232: drop time-based drain delay (diff) | |
| download | linux-4b8e07951ff53e702bd5d6d21450b17152d124d7.tar.xz linux-4b8e07951ff53e702bd5d6d21450b17152d124d7.zip | |
USB: serial: io_ti: document reason for drain delay
Document that the device line-status register doesn't tell when the
transmitter shift register has emptied and that this is why the
one-character drain delay is needed.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Diffstat (limited to 'drivers/usb/serial/io_ti.c')
| -rw-r--r-- | drivers/usb/serial/io_ti.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c index 75325c2b295e..17720670e06c 100644 --- a/drivers/usb/serial/io_ti.c +++ b/drivers/usb/serial/io_ti.c @@ -2590,6 +2590,10 @@ static int edge_port_probe(struct usb_serial_port *port) if (ret) goto err; + /* + * The LSR does not tell when the transmitter shift register has + * emptied so add a one-character drain delay. + */ port->port.drain_delay = 1; return 0; |