5.10-stable patches

added patches:
	revert-serial-8250-fix-reporting-real-baudrate-value-in-c_ospeed-field.patch

diff --git a/queue-5.10/revert-serial-8250-fix-reporting-real-baudrate-value-in-c_ospeed-field.patch b/queue-5.10/revert-serial-8250-fix-reporting-real-baudrate-value-in-c_ospeed-field.patch
new file mode 100644 (file)
index 0000000..924c1b5
--- /dev/null
+++ b/queue-5.10/revert-serial-8250-fix-reporting-real-baudrate-value-in-c_ospeed-field.patch
@@ -0,0 +1,88 @@
+From d02b006b29de14968ba4afa998bede0d55469e29 Mon Sep 17 00:00:00 2001
+From: Johan Hovold <johan@kernel.org>
+Date: Thu, 7 Oct 2021 15:31:46 +0200
+Subject: Revert "serial: 8250: Fix reporting real baudrate value in c_ospeed field"
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From: Johan Hovold <johan@kernel.org>
+
+commit d02b006b29de14968ba4afa998bede0d55469e29 upstream.
+
+This reverts commit 32262e2e429cdb31f9e957e997d53458762931b7.
+
+The commit in question claims to determine the inverse of
+serial8250_get_divisor() but failed to notice that some drivers override
+the default implementation using a get_divisor() callback.
+
+This means that the computed line-speed values can be completely wrong
+and results in regular TCSETS requests failing (the incorrect values
+would also be passed to any overridden set_divisor() callback).
+
+Similarly, it also failed to honour the old (deprecated) ASYNC_SPD_FLAGS
+and would break applications relying on those when re-encoding the
+actual line speed.
+
+There are also at least two quirks, UART_BUG_QUOT and an OMAP1510
+workaround, which were happily ignored and that are now broken.
+
+Finally, even if the offending commit were to be implemented correctly,
+this is a new feature and not something which should be backported to
+stable.
+
+Cc: Pali Rohár <pali@kernel.org>
+Fixes: 32262e2e429c ("serial: 8250: Fix reporting real baudrate value in c_ospeed field")
+Cc: stable <stable@vger.kernel.org>
+Signed-off-by: Johan Hovold <johan@kernel.org>
+Link: https://lore.kernel.org/r/20211007133146.28949-1-johan@kernel.org
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/tty/serial/8250/8250_port.c |   17 -----------------
+ 1 file changed, 17 deletions(-)
+
+--- a/drivers/tty/serial/8250/8250_port.c
++++ b/drivers/tty/serial/8250/8250_port.c
+@@ -2547,19 +2547,6 @@ static unsigned int serial8250_get_divis
+       return serial8250_do_get_divisor(port, baud, frac);
+ }
+ 
+-static unsigned int serial8250_compute_baud_rate(struct uart_port *port,
+-                                               unsigned int quot)
+-{
+-      if ((port->flags & UPF_MAGIC_MULTIPLIER) && quot == 0x8001)
+-              return port->uartclk / 4;
+-      else if ((port->flags & UPF_MAGIC_MULTIPLIER) && quot == 0x8002)
+-              return port->uartclk / 8;
+-      else if (port->type == PORT_NPCM)
+-              return DIV_ROUND_CLOSEST(port->uartclk - 2 * (quot + 2), 16 * (quot + 2));
+-      else
+-              return DIV_ROUND_CLOSEST(port->uartclk, 16 * quot);
+-}
+-
+ static unsigned char serial8250_compute_lcr(struct uart_8250_port *up,
+                                           tcflag_t c_cflag)
+ {
+@@ -2701,14 +2688,11 @@ void serial8250_update_uartclk(struct ua
+ 
+       baud = serial8250_get_baud_rate(port, termios, NULL);
+       quot = serial8250_get_divisor(port, baud, &frac);
+-      baud = serial8250_compute_baud_rate(port, quot);
+ 
+       serial8250_rpm_get(up);
+       spin_lock_irqsave(&port->lock, flags);
+ 
+       uart_update_timeout(port, termios->c_cflag, baud);
+-      if (tty_termios_baud_rate(termios))
+-              tty_termios_encode_baud_rate(termios, baud, baud);
+ 
+       serial8250_set_divisor(port, baud, quot, frac);
+       serial_port_out(port, UART_LCR, up->lcr);
+@@ -2742,7 +2726,6 @@ serial8250_do_set_termios(struct uart_po
+ 
+       baud = serial8250_get_baud_rate(port, termios, old);
+       quot = serial8250_get_divisor(port, baud, &frac);
+-      baud = serial8250_compute_baud_rate(port, quot);
+ 
+       /*
+        * Ok, we're now changing the port state.  Do it with

diff --git a/queue-5.10/series b/queue-5.10/series
index 3c1ff24769488fd68b86d323203c3fbe45b4c473..6f90c38cc393e920a021652b5e7980a6d561e8f6 100644 (file)
--- a/queue-5.10/series
+++ b/queue-5.10/series
@@ -22,3 +22,4 @@ cifs-revalidate-mapping-when-doing-direct-writes.patch
 cifs-don-t-send-down-the-destination-address-to-sendmsg-for-a-sock_stream.patch
 tools-include-uapi-fix-asm-errno.h-for-parisc-and-xtensa.patch
 video-fbdev-i740fb-error-out-if-pixclock-equals-zero.patch
+revert-serial-8250-fix-reporting-real-baudrate-value-in-c_ospeed-field.patch