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author | Ivo Sieben <meltedpianoman@gmail.com> | 2013-01-28 12:32:01 (GMT) |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-02-04 23:05:04 (GMT) |
commit | 98001214c0436c2b697d696fde3696d32620d394 (patch) | |
tree | 281011943ccd3621272d7188e6a35c3118a7223e /drivers/video/backlight/ot200_bl.c | |
parent | 183d95cdd834381c594d3aa801c1f9f9c0c54fa9 (diff) | |
download | linux-fsl-qoriq-98001214c0436c2b697d696fde3696d32620d394.tar.xz |
tty: Use raw spin lock to protect the TTY read section
The "normal" spin lock that guards the N_TTY line discipline read section
is replaced by a raw spin lock.
On a PREEMP_RT system this prevents unwanted scheduling overhead when data is
read at the same time as data is being received: while RX IRQ threaded handling
is busy a TTY read call is performed from a RT priority > threaded IRQ priority.
The read call tries to take the read section spin lock (held by the threaded
IRQ) which blocks and causes a context switch to/from the threaded IRQ handler
until the spin lock is unlocked.
Signed-off-by: Ivo Sieben <meltedpianoman@gmail.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/video/backlight/ot200_bl.c')
0 files changed, 0 insertions, 0 deletions