From d9b43a10f0d04564c6e05de3728c3cbba64c644d Mon Sep 17 00:00:00 2001 From: "Seymour, Shane M" Date: Mon, 12 Oct 2015 04:31:17 +0000 Subject: st: allow debug output to be enabled or disabled via sysfs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Change st driver to allow enabling or disabling debug output via sysfs file /sys/bus/scsi/drivers/st/debug_flag. Previously the only way to enable debug output was: 1. loading the driver with the module parameter debug_flag=1 2. an ioctl call (this method was also the only way to dynamically disable debug output). To use the ioctl you need a second tape drive (if you are actively testing the first tape drive) since a second process cannot open the first tape drive if it is in use. The this change is only functional if the value of the macro DEBUG in st.c is a non-zero value (which it is by default). Signed-off-by: Shane Seymour Reviewed-by: Laurence Oberman Acked-by: Kai Mäkisara Signed-off-by: James Bottomley --- Documentation/ABI/testing/sysfs-driver-st | 12 ++++++++++++ 1 file changed, 12 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-driver-st (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/sysfs-driver-st b/Documentation/ABI/testing/sysfs-driver-st new file mode 100644 index 000000000000..ba5d77008a85 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-st @@ -0,0 +1,12 @@ +What: /sys/bus/scsi/drivers/st/debug_flag +Date: October 2015 +Kernel Version: ?.? +Contact: shane.seymour@hpe.com +Description: + This file allows you to turn debug output from the st driver + off if you write a '0' to the file or on if you write a '1'. + Note that debug output requires that the module be compiled + with the #define DEBUG set to a non-zero value (this is the + default). If DEBUG is set to 0 then this file will not + appear in sysfs as its presence is conditional upon debug + output support being compiled into the module. -- cgit v1.2.3