From 0be916a68c8ada0c98d4c14058717175a367ee87 Mon Sep 17 00:00:00 2001 From: Manikanta Guntupalli Date: Thu, 16 Nov 2023 19:10:02 +0530 Subject: Documentation: devices.txt: Update ttyUL major number allocation details Describe when uartlite driver uses static/dynamic allocation for major number based on maximum number of uartlite serial ports. Signed-off-by: Manikanta Guntupalli Link: https://lore.kernel.org/r/20231116134003.3762725-2-manikanta.guntupalli@amd.com Signed-off-by: Greg Kroah-Hartman --- Documentation/admin-guide/devices.txt | 3 +++ 1 file changed, 3 insertions(+) (limited to 'Documentation/admin-guide') diff --git a/Documentation/admin-guide/devices.txt b/Documentation/admin-guide/devices.txt index 839054923530..94c98be1329a 100644 --- a/Documentation/admin-guide/devices.txt +++ b/Documentation/admin-guide/devices.txt @@ -2704,6 +2704,9 @@ ... 185 = /dev/ttyNX15 Hilscher netX serial port 15 186 = /dev/ttyJ0 JTAG1 DCC protocol based serial port emulation + + If maximum number of uartlite serial ports is more than 4, then the driver + uses dynamic allocation instead of static allocation for major number. 187 = /dev/ttyUL0 Xilinx uartlite - port 0 ... 190 = /dev/ttyUL3 Xilinx uartlite - port 3 -- cgit From 39ff20f5fd4481c9acf3b75c7b705b1ec6604588 Mon Sep 17 00:00:00 2001 From: Tomas Mudrunka Date: Mon, 20 Nov 2023 12:14:51 +0100 Subject: /proc/sysrq-trigger: accept multiple keys at once This way we can do: `echo _reisub > /proc/sysrq-trigger` Instead of: `for i in r e i s u b; do echo "$i" > /proc/sysrq-trigger; done;` This can be very useful when trying to execute sysrq combo remotely or from userspace. When sending keys in multiple separate writes, userspace (eg. bash or ssh) can be killed before whole combo is completed. Therefore putting all keys in single write is more robust approach. Signed-off-by: Tomas Mudrunka Reviewed-by: Jiri Slaby Link: https://lore.kernel.org/r/20231120111451.527952-1-tomas.mudrunka@gmail.com Signed-off-by: Greg Kroah-Hartman --- Documentation/admin-guide/sysrq.rst | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'Documentation/admin-guide') diff --git a/Documentation/admin-guide/sysrq.rst b/Documentation/admin-guide/sysrq.rst index 51906e47327b..2f2e5bd440f9 100644 --- a/Documentation/admin-guide/sysrq.rst +++ b/Documentation/admin-guide/sysrq.rst @@ -75,10 +75,19 @@ On other submit a patch to be included in this section. On all - Write a character to /proc/sysrq-trigger. e.g.:: + Write a single character to /proc/sysrq-trigger. + Only the first character is processed, the rest of the string is + ignored. However, it is not recommended to write any extra characters + as the behavior is undefined and might change in the future versions. + E.g.:: echo t > /proc/sysrq-trigger + Alternatively, write multiple characters prepended by underscore. + This way, all characters will be processed. E.g.:: + + echo _reisub > /proc/sysrq-trigger + The :kbd:`` is case sensitive. What are the 'command' keys? -- cgit