From: Ralf Baechle <ralf@linux-mips.org>
To: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org, LKML <linux-kernel@vger.kernel.org>,
huhb@lemote.com, yanh@lemote.com, Zhang Le <r0bertz@gentoo.org>,
Thomas Gleixner <tglx@linutronix.de>,
Nicholas Mc Guire <der.herr@hofr.at>,
zhangfx@lemote.com, liujl@lemote.com
Subject: Re: [PATCH -queue v0 4/6] [loongson] add basic fuloong2f support
Date: Fri, 6 Nov 2009 09:30:42 +0100 [thread overview]
Message-ID: <20091106083042.GA17723@linux-mips.org> (raw)
In-Reply-To: <1257485984.2299.21.camel@falcon.domain.org>
On Fri, Nov 06, 2009 at 01:39:44PM +0800, Wu Zhangjin wrote:
> > > + if ((LOONGSON_INTISR & LOONGSON_INTEN) & LOONGSON_INT_BIT_INT0) {
> > > + imr = inb(0x21) | (inb(0xa1) << 8);
> > > + isr = inb(0x20) | (inb(0xa0) << 8);
> > > + isr &= ~0x4; /* irq2 for cascade */
> > > + isr &= ~imr;
> > > + irq = ffs(isr) - 1;
> > > + }
> >
> > Any reason why you're not using i8259_irq() from <asm/i8259.h> here?
> > That function not only gets the locking right, it also minimizes the number
> > of accesses to the i8259 - which even on modern silicon can be stuningly
> > slow.
> Just asked Yanhua, He told me there is a bug in cs5536, if using the
> i8259_irq() directly, we can not get the irq. and just tried it, the
> kernel hang on booting.
Wonderful. Even 30 years after it was built there are still new i8259
bugs :-)
This is probably worth a comment in the code.
Ralf
next prev parent reply other threads:[~2009-11-06 8:29 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1257325319.git.wuzhangjin@gmail.com>
2009-11-04 9:04 ` [PATCH -queue v0 1/6] [loongson] add basic loongson-2f support Wu Zhangjin
2009-11-04 10:28 ` Arnaud Patard
2009-11-04 11:04 ` Wu Zhangjin
2009-11-04 11:19 ` Ralf Baechle
2009-11-04 15:23 ` Wu Zhangjin
2009-11-04 20:15 ` Ralf Baechle
2009-11-05 1:39 ` Wu Zhangjin
2009-11-05 8:45 ` Ralf Baechle
2009-11-04 11:36 ` Arnaud Patard
2009-11-05 9:18 ` Ralf Baechle
2009-11-05 9:48 ` Wu Zhangjin
2009-11-05 10:28 ` Ralf Baechle
2009-11-05 11:00 ` Wu Zhangjin
2009-11-04 9:05 ` [PATCH -queue v0 2/6] [loongson] oprofile: avoid do_IRQ for perfcounter when the interrupt is from bonito Wu Zhangjin
2009-11-04 9:05 ` [PATCH -queue v0 3/6] [loongson] add basic cs5536 vsm support Wu Zhangjin
2009-11-04 9:05 ` [PATCH -queue v0 4/6] [loongson] add basic fuloong2f support Wu Zhangjin
2009-11-05 13:16 ` Ralf Baechle
2009-11-05 14:44 ` Wu Zhangjin
2009-11-06 5:39 ` Wu Zhangjin
2009-11-06 8:30 ` Ralf Baechle [this message]
2009-11-06 10:05 ` Wu Zhangjin
2009-11-06 8:34 ` Wu Zhangjin
2009-11-04 9:06 ` [PATCH -queue v0 5/6] [loongson] rtc: enable legacy RTC driver on fuloong2f Wu Zhangjin
2009-11-04 10:40 ` Arnaud Patard
2009-11-04 11:18 ` Wu Zhangjin
2009-11-04 11:34 ` Arnaud Patard
2009-11-04 14:15 ` Ralf Baechle
2009-11-04 15:12 ` Wu Zhangjin
2009-11-04 9:06 ` [PATCH -queue v0 6/6] [loongson] add default config file for fuloong2f Wu Zhangjin
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