Le 17/06/2014 21:28, Peter Hurley a écrit : > 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 Seems to be pmac_zilog, from dmesg : pmac_zilog: 0.6 (Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>) scc.0: ttyS0 at MMIO 0x50f0c022 (irq = 4, base_baud = 230400) is a Z85c30 ESCC - Serial port scc.1: ttyS1 at MMIO 0x50f0c020 (irq = 4, base_baud = 230400) is a Z85c30 ESCC - Serial port If needed, I can test the fix. Thank you. Regards, Laurent > 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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