On 06/17/2014 02:48 PM, Laurent Vivier wrote:
Hi, I'm not subscribed to these mailing lists, so CC: me. I'm playing for some days with a kernel 3.15 on an old mac performa 575 and it seems that the serial port is broken. When I log on using the console on the serial port it seems there is an screen refresh added after each character I send.
What uart driver is this happening on? This is a known bug being worked on for these uart drivers: sunsab sunzilog ip22zilog pmac_zilog Regards, Peter Hurley
A little demo : http://asciinema.org/a/10211 [at 3:20] I bisect and I found this commit : commit 717f3bbab3c7628736ef738fdbf3d9a28578c26c Author: Seth Bollinger <sethb@xxxxxxxx> Date: Tue Mar 25 12:55:37 2014 -0500 serial_core: Fix conditional start_tx on ring buffer not empty If the serial_core ring buffer empties just as the tty layer receives an XOFF, then start_tx will never be called when the tty layer receives an XON as the serial_core ring buffer is empty. This will possibly leave a few bytes trapped in the fifo for drivers that disable the transmitter when flow controlled. Signed-off-by: Seth Bollinger <sethb@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> If I revert it, all works fine : http://asciinema.org/a/10212 Regards, Laurent
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