path: root/Documentation/serial
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authorPeter Hurley <peter@hurleysoftware.com>2014-09-02 17:39:15 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-09-08 16:22:42 -0700
commitdb106df32d679db151b48a09543b03ee41cb2580 (patch)
treebef38581727c0696e7aac02df61ceb9a8a093685 /Documentation/serial
parentfba594a848f6f35417a358565086d22c533c19c8 (diff)
serial: Fix send_xchar() handlers
START_CHAR() & STOP_CHAR() can be disabled if set to '\0' (__DISABLED_CHAR). UART drivers which define a send_xchar() handler must not transmit __DISABLED_CHAR. Document requirement. Affected drivers: sunsab sunhv cc: David S. Miller <davem@davemloft.net> cc: <sparclinux@vger.kernel.org> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/serial')
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/serial/driver b/Documentation/serial/driver
index 3bba1aeb799c..ba64e4b892e9 100644
--- a/Documentation/serial/driver
+++ b/Documentation/serial/driver
@@ -140,6 +140,8 @@ hardware.
will append the character to the circular buffer and then call
start_tx() / stop_tx() to flush the data out.
+ Do not transmit if ch == '\0' (__DISABLED_CHAR).
Locking: none.
Interrupts: caller dependent.

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