releases/4.19.54/sunhv-fix-device-naming-inconsistency-between-sunhv_console-and-sunhv_reg.patch

   1 From foo@baz Wed 19 Jun 2019 02:34:37 PM CEST
   2 From: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
   3 Date: Tue, 11 Jun 2019 17:38:37 +0200
   4 Subject: sunhv: Fix device naming inconsistency between sunhv_console and sunhv_reg
   5
   6 From: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
   7
   8 [ Upstream commit 07a6d63eb1b54b5fb38092780fe618dfe1d96e23 ]
   9
  10 In d5a2aa24, the name in struct console sunhv_console was changed from "ttyS"
  11 to "ttyHV" while the name in struct uart_ops sunhv_pops remained unchanged.
  12
  13 This results in the hypervisor console device to be listed as "ttyHV0" under
  14 /proc/consoles while the device node is still named "ttyS0":
  15
  16 root@osaka:~# cat /proc/consoles
  17 ttyHV0               -W- (EC p  )    4:64
  18 tty0                 -WU (E     )    4:1
  19 root@osaka:~# readlink /sys/dev/char/4:64
  20 ../../devices/root/f02836f0/f0285690/tty/ttyS0
  21 root@osaka:~#
  22
  23 This means that any userland code which tries to determine the name of the
  24 device file of the hypervisor console device can not rely on the information
  25 provided by /proc/consoles. In particular, booting current versions of debian-
  26 installer inside a SPARC LDOM will fail with the installer unable to determine
  27 the console device.
  28
  29 After renaming the device in struct uart_ops sunhv_pops to "ttyHV" as well,
  30 the inconsistency is fixed and it is possible again to determine the name
  31 of the device file of the hypervisor console device by reading the contents
  32 of /proc/console:
  33
  34 root@osaka:~# cat /proc/consoles
  35 ttyHV0               -W- (EC p  )    4:64
  36 tty0                 -WU (E     )    4:1
  37 root@osaka:~# readlink /sys/dev/char/4:64
  38 ../../devices/root/f02836f0/f0285690/tty/ttyHV0
  39 root@osaka:~#
  40
  41 With this change, debian-installer works correctly when installing inside
  42 a SPARC LDOM.
  43
  44 Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
  45 Signed-off-by: David S. Miller <davem@davemloft.net>
  46 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  47 ---
  48  drivers/tty/serial/sunhv.c |    2 +-
  49  1 file changed, 1 insertion(+), 1 deletion(-)
  50
  51 --- a/drivers/tty/serial/sunhv.c
  52 +++ b/drivers/tty/serial/sunhv.c
  53 @@ -397,7 +397,7 @@ static const struct uart_ops sunhv_pops
  54  static struct uart_driver sunhv_reg = {
  55         .owner                  = THIS_MODULE,
  56         .driver_name            = "sunhv",
  57 -       .dev_name               = "ttyS",
  58 +       .dev_name               = "ttyHV",
  59         .major                  = TTY_MAJOR,
  60  };
  61