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From: Tim Douglas <me@timdoug.com>
To: gregkh@linuxfoundation.org, jirislaby@kernel.org
Cc: linux-serial@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-kernel@vger.kernel.org, maddy@linux.ibm.com,
	mpe@ellerman.id.au, npiggin@gmail.com, chleroy@kernel.org,
	Tim Douglas <me@timdoug.com>
Subject: [PATCH 0/2] serial: pmac_zilog: two receive fixes
Date: Mon, 12 Oct 2026 21:35:39 -0400	[thread overview]
Message-ID: <20261013013541.4535-1-me@timdoug.com> (raw)

These two patches fix receive problems in pmac_zilog that I ran into
while bringing up the serial ports on a Performa 6200CD, a NuBus Power
Macintosh. The first stops data received on one port from being left in
its flip buffer while the other port is open. The second makes received
breaks visible; until now they arrived as plain NUL characters.

I tested both on the 6200, running 7.2.8 with an out-of-tree platform
port and a loopback plug on the printer port. Without the series, only 3
of 8 bytes written to ttyPZ1 came back while ttyPZ0 was open, and a
break sent with tcsendbreak() arrived as a NUL with no break counted.
With the series, all 8 bytes came back, the break was counted, and with
PARMRK set it read as FF 00 00.

The series also builds on v7.3-rc7 with pmac32_defconfig and W=1 without
warnings. I have not tested 68k Macs or macio Power Macs.

I found these bugs and wrote the patches with the help of Claude Opus
5.5. I have reviewed both patches and run the tests on the 6200 myself.

Tim Douglas (2):
  serial: pmac_zilog: push received data to the port that received it
  serial: pmac_zilog: report received breaks

 drivers/tty/serial/pmac_zilog.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)


base-commit: 24a19b953e2a3d0ea5a8c4951a0ab8f32720c907
-- 
2.54.0 (Apple Git-157)


             reply	other threads:[~2026-10-13  1:35 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-13  1:35 Tim Douglas [this message]
2026-10-13  1:35 ` [PATCH 1/2] serial: pmac_zilog: push received data to the port that received it Tim Douglas
2026-10-13  1:48   ` sashiko-bot
2026-10-13  1:35 ` [PATCH 2/2] serial: pmac_zilog: report received breaks Tim Douglas
2026-10-13  1:44   ` sashiko-bot

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