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Peter Hurley authored
Commit 717f3bba, 'serial_core: Fix conditional start_tx on ring buffer not empty' exposes an incorrect assumption in several drivers' start_tx methods; the tx ring buffer can, in fact, be empty when restarting tx while performing flow control. Affected drivers: sunsab.c ip22zilog.c pmac_zilog.c sunzilog.c m32r_sio.c imx.c Other in-tree serial drivers either are not affected or already test for empty tx ring buffer before transmitting. Test for empty tx ring buffer in start_tx() method, after transmitting x_char (if applicable). Reported-by:
Aaro Koskinen <aaro.koskinen@iki.fi> Cc: Seth Bollinger <sethb@digi.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by:
Peter Hurley <peter@hurleysoftware.com> Cc: stable <stable@vger.kernel.org> # 3.15 Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
c557d392