Messages in this thread | | | Date | Sun, 29 Jul 2007 09:41:04 -0600 | From | Robert Hancock <> | Subject | Re: IRQF_DISABLED problem |
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David Miller wrote: > From: Arjan van de Ven <arjan@infradead.org> > Date: Fri, 27 Jul 2007 13:11:56 -0700 > >> On Thu, 2007-07-26 at 16:17 -0700, Linus Torvalds wrote: >>> On Thu, 26 Jul 2007, Linus Torvalds wrote: >>>> (c) "one IRQF_DISABLED means that everything runs disabled". This is >>>> quite possibly buggy. >>> (Side note: I'm not claiming this (or it's mirror image (d)) is really any >>> better/worse than the current behaviour from a theoretical standpoint, but >>> at least the current behaviour is _tested_, which makes it better in >>> practice. So if we want to change this, I think we want to change it to >>> something that is _obviously_ better). >> my personal preference would actually be to just never enable >> interrupts. It's the fastest solution obviously, the most friendly on >> stack and.. well simplest. Drivers no longer need to play some of the >> games that they do today. And while there is an argument that this may >> introduce a bit of latency... I'm not really convinced. > > If you have a "chirpy" serial controller with only a 1 byte > fifo, even a quite reasonable interrupt handler can cause > receive characters to get lost if you disable interrupts during > the entirety of it's execution. > > It really is needed. > > And it's just plain rude to disable interrupts when it isn't > absolutely necessary.
Does anyone really use those serial controllers with no FIFO anymore? They've never been reliable for remotely high speeds..
-- Robert Hancock Saskatoon, SK, Canada To email, remove "nospam" from hancockr@nospamshaw.ca Home Page: http://www.roberthancock.com/
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