On Wed, Nov 07, 2018 at 11:26:56AM -0800, Doug Anderson wrote: > Hi, > > On Wed, Nov 7, 2018 at 10:23 AM Andy Shevchenko > <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote: > > > > 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. > > > > It seems your forgot console people to Cc. > > Can you be more specific, please? Which section of the "MAINTAINERS" > file should I be looking at for the "console" you are thinking of? I have added them to Cc list: Petr, Sergey, and Steven. > Certainly there are lots of hits for "console" in MAINTAINERS but I > don't think I see any that are relevant that I missed. Grepping: > Ah! Based on who you added to the CC list I guess you meant to CC > "printk" folks? Correct. > PRINTK > M: Petr Mladek <pmladek@xxxxxxxx> > M: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx> > R: Steven Rostedt <rostedt@xxxxxxxxxxx> > S: Maintained > F: kernel/printk/ > F: include/linux/printk.h > I'd be happy to CC those folks on future spins (if there are any). > I'm not convinced that these patches are directly relevant to the > printk subsystem, but I'm always happy for more people to have a > chance to review patches. If you look retrospectively in the mailing lists, you can find that they are doing most of the console core work, which I believe includes SysRq behaviour. So, don't be confused their names are listed under PRINTK. > Hopefully anyone who needs this patch can find it on one of the > relevant mailing lists. I screwed up and missed LKML this time > around, but there are plenty of other mailing lists here that it could > be found on. If requested I'm also happy to re-post the same series > adding those 3 people if that's what everyone wants. -- With Best Regards, Andy Shevchenko
