Messages in this thread | | | From | Ondrej Zary <> | Subject | Re: [PATCH 4/6] g_NCR5380: Add IRQ auto-configuration for HP C2502 | Date | Thu, 3 Nov 2016 09:00:56 +0100 |
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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
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