5.4-stable patches

added patches:
	serial-8250-store-to-lsr_save_flags-after-lsr-read.patch

diff --git a/queue-5.4/serial-8250-store-to-lsr_save_flags-after-lsr-read.patch b/queue-5.4/serial-8250-store-to-lsr_save_flags-after-lsr-read.patch
new file mode 100644 (file)
index 0000000..134bf1e
--- /dev/null
+++ b/queue-5.4/serial-8250-store-to-lsr_save_flags-after-lsr-read.patch
@@ -0,0 +1,46 @@
+From be03b0651ffd8bab69dfd574c6818b446c0753ce Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
+Date: Fri, 20 May 2022 13:35:41 +0300
+Subject: serial: 8250: Store to lsr_save_flags after lsr read
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
+
+commit be03b0651ffd8bab69dfd574c6818b446c0753ce upstream.
+
+Not all LSR register flags are preserved across reads. Therefore, LSR
+readers must store the non-preserved bits into lsr_save_flags.
+
+This fix was initially mixed into feature commit f6f586102add ("serial:
+8250: Handle UART without interrupt on TEMT using em485"). However,
+that feature change had a flaw and it was reverted to make room for
+simpler approach providing the same feature. The embedded fix got
+reverted with the feature change.
+
+Re-add the lsr_save_flags fix and properly mark it's a fix.
+
+Link: https://lore.kernel.org/all/1d6c31d-d194-9e6a-ddf9-5f29af829f3@linux.intel.com/T/#m1737eef986bd20cf19593e344cebd7b0244945fc
+Fixes: e490c9144cfa ("tty: Add software emulated RS485 support for 8250")
+Cc: stable <stable@kernel.org>
+Acked-by: Uwe Kleine-König <u.kleine-koenig@penugtronix.de>
+Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
+Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
+Link: https://lore.kernel.org/r/f4d774be-1437-a550-8334-19d8722ab98c@linux.intel.com
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/tty/serial/8250/8250_port.c |    2 ++
+ 1 file changed, 2 insertions(+)
+
+--- a/drivers/tty/serial/8250/8250_port.c
++++ b/drivers/tty/serial/8250/8250_port.c
+@@ -1476,6 +1476,8 @@ static inline void __stop_tx(struct uart
+ 
+       if (em485) {
+               unsigned char lsr = serial_in(p, UART_LSR);
++              p->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
++
+               /*
+                * To provide required timeing and allow FIFO transfer,
+                * __stop_tx_rs485() must be called only when both FIFO and

diff --git a/queue-5.4/series b/queue-5.4/series
index 93c029e19449295edb20dda513b9d36610df92ab..e355cc3f469be640284235d49ade9d0ed6d7f7a7 100644 (file)
--- a/queue-5.4/series
+++ b/queue-5.4/series
@@ -223,3 +223,4 @@ usb-serial-option-add-support-for-cinterion-mv31-with-new-baseline.patch
 usb-serial-io_ti-add-agilent-e5805a-support.patch
 usb-dwc2-fix-memory-leak-in-dwc2_hcd_init.patch
 usb-gadget-lpc32xx_udc-fix-refcount-leak-in-lpc32xx_udc_probe.patch
+serial-8250-store-to-lsr_save_flags-after-lsr-read.patch