Re: Serial-Core: USB-Serial port current issues.

["Luiz Fernando N. Capitulino" <lcapitulino@mandriva.com.br>]

On Thu, 15 Jun 2006 09:07:05 -0700
Greg KH <gregkh@suse.de> wrote:

| On Thu, Jun 15, 2006 at 10:29:40AM -0300, Luiz Fernando N. Capitulino wrote:
| > On Wed, 14 Jun 2006 17:53:08 -0700
| > Pete Zaitcev <zaitcev@redhat.com> wrote:
| > 
| > | On Wed, 14 Jun 2006 17:38:24 -0300, "Luiz Fernando N. Capitulino" <lcapitulino@mandriva.com.br> wrote:
| > | 
| > | >  I think BUG_ON(in_interrupt()) does the job. I'll try it here, and
| > | > if it doesn't trigger I'll submit a patch to Andrew only for
| > | > testing porpuses (ie, not for mainline).
| > | 
| > | Luiz, you can't be serious! You have to do a review and write call paths
| > | on a piece of paper or however you prefer to do it. Your testing is
| > | extremely limited as we know, you don't even have a null-modem cable.
| > | So if the patch does not trip in your testing it tells you absolutely
| > | nothing. But even in context of AKPM's tree you can't rely on run-time
| > | checks to pick this sort of things.
| > 
| >  Hey, take it easy. :)
| > 
| >  I won't test it in my patches. I'll hack the Serial Core code and add
| > debug code just before every call to those functions we want to know
| > whether they run in interrupt context or not.
| > 
| >  Yeah, I know, it's still limited because the driver itself can call its
| > methods directly in interrupt context. But I think it's a good start.
| > 
| > | And putting a BUG in there is irresponsible too. It's such a critical
| > | subsystem. Drop bytes or return zero modem lines, but do not bug out.
| > 
| >  Well, I want the easier, fastest and non-questionable way to know whether
| > they are called from an interrupt context or not. The first thing that
| > came to my mind was: blow up everything if it has been called in
| > interrupt context.
| > 
| >  But I'm open for suggestions, of course.
| 
| WARN_ON(in_interrupt());
| is much nicer.  It gives you a full dump, yet lets the machine keep
| working so that users can actually give you the bug report.

 Ok. Working on it right now.

 BTW, forgot to say, I do have a null-modem cable now. As soon as
ftdi_sio is ported, we can do all the missing tests.

-- 
Luiz Fernando N. Capitulino