Re: [PATCH] 8250: option 'force_polling' for buggy IRQs

From	Theodore Ts'o <tytso@mit.edu>
Newsgroups	linux.kernel
Subject	Re: [PATCH] 8250: option 'force_polling' for buggy IRQs
Date	2016-07-27 15:40 +0200
Message-ID	<rZxe2-8qU-19@gated-at.bofh.it> (permalink)
References	(2 earlier) <rZ922-1qi-19@gated-at.bofh.it> <rZc9z-3vF-21@gated-at.bofh.it> <rZdfj-47u-1@gated-at.bofh.it> <rZvOV-7FO-3@gated-at.bofh.it> <rZvYB-7Js-19@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, Jul 27, 2016 at 02:14:24PM +0200, Max Staudt wrote:
> > If you set the IRQ to 0 it should poll anyway (0 means 'no IRQ') so I
> > don't think the option is needed. At least it seems sufficient to get me
> > by when I meet buggy PC BIOSes and the like
> 
> That's exactly what the patch does - but if there is already a way to set the
> IRQ to 0, I would of course prefer to use that.
> 
> It seems I haven't found the trick you're using - could you please tell me how
> you set the IRQ to 0?  I can't change it in the BIOS, so I have to do it at
> the kernel level at the latest.

So the problem is that you can't use setserial because you want to use
this port for your console?  And so you don't want to set it in an initscript?

The one thing which is really unfortunate with this patch is that it's
a global, so it forces polling for *all* serial ports.  And it may be
that it's only base ports on the motherboard which needs this hack.

I wonder if it would just be simpler to make it be a CONFIG option
which causes the irq value to zero in arch/x86/include/asm/serial.h?

					- Ted

Thread

Re: [PATCH] 8250: option 'force_polling' for buggy IRQs Max Staudt <mstaudt@suse.de> - 2016-07-26 13:50 +0200
  Re: [PATCH] 8250: option 'force_polling' for buggy IRQs Greg KH <gregkh@linuxfoundation.org> - 2016-07-26 17:10 +0200
    Re: [PATCH] 8250: option 'force_polling' for buggy IRQs Max Staudt <mstaudt@suse.de> - 2016-07-26 18:20 +0200
      Re: [PATCH] 8250: option 'force_polling' for buggy IRQs One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-07-27 14:10 +0200
        Re: [PATCH] 8250: option 'force_polling' for buggy IRQs Max Staudt <mstaudt@suse.de> - 2016-07-27 14:20 +0200
          Re: [PATCH] 8250: option 'force_polling' for buggy IRQs Theodore Ts'o <tytso@mit.edu> - 2016-07-27 15:40 +0200
            Re: [PATCH] 8250: option 'force_polling' for buggy IRQs One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-07-27 22:10 +0200
            Re: [PATCH] 8250: option 'force_polling' for buggy IRQs Max Staudt <mstaudt@suse.de> - 2016-07-28 12:00 +0200
              Re: [PATCH] 8250: option 'force_polling' for buggy IRQs Greg KH <gregkh@linuxfoundation.org> - 2016-07-28 16:50 +0200
                Re: [PATCH] 8250: option 'force_polling' for buggy IRQs Theodore Ts'o <tytso@mit.edu> - 2016-07-28 18:10 +0200
              Re: [PATCH] 8250: option 'force_polling' for buggy IRQs ebiederm@xmission.com (Eric W. Biederman) - 2016-07-28 21:00 +0200
                Re: [PATCH] 8250: option 'force_polling' for buggy IRQs One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-07-29 11:30 +0200
                Re: [PATCH] 8250: option 'force_polling' for buggy IRQs Max Staudt <mstaudt@suse.de> - 2016-07-29 12:00 +0200
                Re: [PATCH] 8250: option 'force_polling' for buggy IRQs ebiederm@xmission.com (Eric W. Biederman) - 2016-07-29 20:00 +0200
                Re: [PATCH] 8250: option 'force_polling' for buggy IRQs One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-08-01 17:30 +0200

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