From: Greg Kroah-Hartman Date: Mon, 20 Jun 2022 09:42:12 +0000 (+0200) Subject: 4.19-stable patches X-Git-Tag: v5.4.200~34 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=52350db562d3c23a09cadda011ecf23bef3c6107;p=thirdparty%2Fkernel%2Fstable-queue.git 4.19-stable patches added patches: serial-8250-store-to-lsr_save_flags-after-lsr-read.patch --- diff --git a/queue-4.19/serial-8250-store-to-lsr_save_flags-after-lsr-read.patch b/queue-4.19/serial-8250-store-to-lsr_save_flags-after-lsr-read.patch new file mode 100644 index 00000000000..bbb3f1bbf9e --- /dev/null +++ b/queue-4.19/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?= +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 + +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 +Acked-by: Uwe Kleine-König +Signed-off-by: Uwe Kleine-König +Signed-off-by: Ilpo Järvinen +Link: https://lore.kernel.org/r/f4d774be-1437-a550-8334-19d8722ab98c@linux.intel.com +Signed-off-by: Greg Kroah-Hartman +--- + 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 +@@ -1522,6 +1522,8 @@ 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-4.19/series b/queue-4.19/series index f61cbfc9ce6..017e13daa71 100644 --- a/queue-4.19/series +++ b/queue-4.19/series @@ -214,3 +214,4 @@ 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