From: Ondrej Zary <linux@rainbow-software.org>
To: Finn Thain <fthain@telegraphics.com.au>
Cc: Christoph Hellwig <hch@infradead.org>,
linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/6] g_NCR5380: Add IRQ auto-configuration for HP C2502
Date: Thu, 3 Nov 2016 09:00:56 +0100 [thread overview]
Message-ID: <201611030900.56371.linux@rainbow-software.org> (raw)
In-Reply-To: <alpine.LNX.2.00.1611022056450.12392@nippy.intranet>
On Thursday 03 November 2016, Finn Thain wrote:
> On Wed, 2 Nov 2016, Ondrej Zary wrote:
> > > Also, you've ignored the irq module parameters. From the user's point
> > > of view, surely the least surprising thing is to attempt to configure
> > > the card for whatever irq the user asked for.
> >
> > I haven't. NCR5380_find_irq is only called when irq is set to IRQ_AUTO.
>
> My mistake.
>
> > > If the specified irq isn't supported by the board, just log an error
> > > and fail. If you want to be user friendly, print a message to tell
> > > them what irqs the card supports.
> >
> > If the IRQ is not supported (or does not work), user gets a warning and
> > the driver continues with IRQ disabled.
> >
> > > If the user asks for IRQ_AUTO, just configure the board for a
> > > hard-coded default, say 9, and print a warning message to say so.
> >
> > The card is almost Plug&Play. The base address is already configured
> > automatically by the driver so doing the same for IRQ makes sense.
>
> Why don't we see any other drivers doing this?
Many ISA sound card drivers do this - there's even a function for this:
static int snd_legacy_find_free_irq(int *irq_table)
Unfortunately, it's defined in ALSA headers and even protected with an #ifdef.
> If the card was really plug and play, I expect we would just call
> pnp_irq(), as the other PNP drivers do.
The card predates the PnP standard so we can't.
> > > Either way, if request_irq fails just continue with NO_IRQ, as per
> > > usual.
> > >
> > > To me that's the most flexible and least surprising behaviour. But
> > > again, if someone with more ISA knowledge wishes to weigh in, that's
> > > fine too.
--
Ondrej Zary
next prev parent reply other threads:[~2016-11-03 8:01 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-31 20:18 [PATCH 0/6] (g_)NCR5380: Improve IRQ probing and some fixes Ondrej Zary
2016-10-31 20:18 ` [PATCH 1/6] NCR5380: Use probe_irq_*() for IRQ probing Ondrej Zary
2016-11-02 7:45 ` Finn Thain
2016-11-02 8:00 ` Ondrej Zary
2016-11-03 2:16 ` Finn Thain
2016-10-31 20:18 ` [PATCH 2/6] g_NCR5380: Test the IRQ before accepting it Ondrej Zary
2016-11-02 7:45 ` Finn Thain
2016-11-02 19:16 ` Ondrej Zary
2016-11-03 2:17 ` Finn Thain
2016-10-31 20:18 ` [PATCH 3/6] g_NCR5380: Check for chip presence before calling NCR5380_init() Ondrej Zary
2016-11-02 7:46 ` Finn Thain
2016-10-31 20:18 ` [PATCH 4/6] g_NCR5380: Add IRQ auto-configuration for HP C2502 Ondrej Zary
2016-11-02 7:46 ` Finn Thain
2016-11-02 8:29 ` Ondrej Zary
2016-11-03 2:17 ` Finn Thain
2016-11-03 8:00 ` Ondrej Zary [this message]
2016-11-04 3:00 ` Finn Thain
2016-10-31 20:18 ` [PATCH 5/6] g_NCR5380: Autoprobe IRQ by default Ondrej Zary
2016-11-02 7:47 ` Finn Thain
2016-12-03 0:39 ` Finn Thain
2016-10-31 20:18 ` [PATCH 6/6] g_NCR5380: Fix release region in error handling Ondrej Zary
2016-11-02 7:49 ` Finn Thain
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