On Tue, Oct 30, 2018 at 03:11:02PM -0700, Douglas Anderson wrote:

I started out this series trying to make sysrq work over the serial
console on qcom_geni_serial, then fell into a rat's nest.

To solve the deadlock I faced when enabling sysrq I tried to borrow
code from '8250_port.c' which avoided grabbing the port lock in
console_write().  ...but since these days I try to run with lockdep on
all the time, I found it caused an annoying lockdep splat (which I
also reproduced on my rk3399 board).  ...so I instead changed my
qcom_geni_serial solution to borrow code from 'msm_serial.c'

I wasn't super happy with the solution in 'msm_serial.c' though.  I
don't like releasing the spinlock there.  Not only is it ugly but it
means we are unlocking / re-locking _all the time_ even though sysrq
characters are rare.  ...so I came up with what I think is a better
solution and then implemented it for qcom_geni_serial.

Since I had a good way to test 8250-based UARTs, I also fixed that
driver to use my new method.  When doing so, I ran into a missing
include in serial_core.h.  NOTE: I didn't have a way to test
msm_serial.c at all, so I didn't switch that (or all other serial
drivers for that matter) to the new method.

NOTE: from a serial point of view v2 is the same as v1 but I've
removed the extra kgdb-related patches and made it obvious that this
is really for all sysrq, not just kgdb.  I've also generally tried to
curate the CCs more properly.

Looks good, thanks for cleaning this up.  All now queued up.

greg k-h