Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 20 Jun 2003 14:00:14 -0400 (EDT) | From | Bill Davidsen <> | Subject | Re: [PATCH] PnP Changes for 2.5.72 |
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On Fri, 20 Jun 2003, Andrey Panin wrote:
> On 171, 06 20, 2003 at 06:55:47AM +0100, Russell King wrote: > > On Thu, Jun 19, 2003 at 11:42:49PM +0000, Adam Belay wrote: > > > I removed avoid_irq_share because the current pnp code, like the previous, does > > > not allow irq sharing. Also it corrupts the device rule structure by replacing > > > it with modified values that may not apply after devices are disabled etc. > > > Is there a set of conditions I could follow to determine if a serial pnp device > > > is capable of irq sharing, and also with which other devices can a capable > > > device share an irq? If so, I could have the resource manager handle this type > > > of situation when few irqs are available. > > > > The problem is one of a lack of historical information on why it was > > added. The driver itself allows serial ports to share interrupts between > > themselves. Maybe tytso knows why the "Rockwell 56K ACF II Fax+Data+Voice > > Modem" is unable to share IRQs? > > It was me who added this crappy quirk. > > My ELine modem which identified itself "Rockwell 56K ACF II Fax+Data+Voice Modem" > was going mad when its IRQ was shared with any device. So I decided to add this > quirk. > > Personally I think that ISA IRQ sharing should be absolutely last resort technic, > because ISA bus was never designed to support IRQ sharing sanely. If you have to > enable ISA PnP device and do not have enough IRQ, you must print BIG FAT WARNING > before doing this. May be kernel config options must be added for brave guys > wanting to use ISA IRQ sharing.
But dumb multiport boards support sharing just fine:
0: uart:16550A port:3F8 irq:4 baud:1200 tx:6 rx:9587 RTS|CTS|DTR|DSR 1: uart:16550A port:2F8 irq:3 baud:9600 tx:9 rx:2 brk:2 2: uart:unknown port:3E8 irq:4 3: uart:unknown port:2E8 irq:3 4: uart:16550A port:1A0 irq:5 baud:9600 tx:0 rx:0 CTS 5: uart:16550A port:1A8 irq:5 baud:9600 tx:0 rx:0 6: uart:16550A port:1B0 irq:5 baud:9600 tx:0 rx:0 7: uart:16550A port:1B8 irq:5 baud:9600 tx:0 rx:0
There's more to it than just "it doesn't work." I note that 2.5.70 still sets the NIC and AHA1540 to the same irq, while 2.4.18 doesn't. I gave up on that, I can't change the hardware (specialty hardware) so I run 2.4 kernels. Someday I'll fight with it.
-- bill davidsen <davidsen@tmr.com> CTO, TMR Associates, Inc Doing interesting things with little computers since 1979. [unhandled content-type:application/pgp-signature] | ![\](/images/icornerr.gif) |