* Andy Shevchenko andriy.shevchenko@linux.intel.com [200916 12:34]:
On Mon, Sep 14, 2020 at 11:09:16AM +0300, Tony Lindgren wrote:
- Andy Shevchenko andriy.shevchenko@linux.intel.com [200910 09:27]:
+Cc: Tony, let me add Tony to the discussion.
On Thu, Sep 10, 2020 at 09:35:27AM +0200, Johan Hovold wrote:
And what about power management which was the reason for wanting this on OMAP in the first place; tty core never calls shutdown() for a console port, not even when it's been detached using the new interface.
That is interesting... Tony, do we have OMAP case working because of luck?
8250_omap won't do anything unless autosuspend_timeout is configured for the uart(s). If configured, then the 8250_omap will idle when console is detached and the PM runtime usage count held by console is decremented, and the configured autosuspend_timeout expires.
The console is still kept open by getty, so I don't see why shutdown() would be called for the console port. But maybe I don't follow what you're concerned about, let me know if you want me to check something :)
Is it possible to test configuration when you have kernel console enabled but no getty is run on it (perhaps something with ssh enabled access)?
Then kernel console should call ->shutdown on detaching, right?
I gave this a quick try and Johan is right, shutdown is not called on console uart still even if detached and no getty running on that uart. I could not figure out easily where exactly this gets blocked.. So far I did try setting port->console = 0 on detach, then init it again on attach.
Regards,
Tony