Hello,

please consider attached patch for the cs4236.c driver module, located
in sound/isa/cs423x/ in the Linux 2.6.11 kernel.

Background: The card/chipset supports an external MIDI interrupt. By
default, this interrupt isn't used (because the isapnp mechanism chooses
a configuration without an assigned interrupt). If the user wishes to
explicitly select an interrupt via the mpu_irq parameter for such a
configured device, it doesn't work: The driver always shows:

isapnp MPU: port=0x330, irq=-1

(note the "irq=-1")

Problem: The driver only allows to set the irq if pnp_irq_valid returns
true for this particular pnp device. This, however, is only true if an
interrupt has already been assigned (pnp_valid_irq returns true if the
flag IORESOURCE_IRQ is set and IORESOURCE_UNSET is not set). If no
interrupt has been assigned so far, IORESOURCE_UNSET is set and
pnp_irq_valid returns false, thereby inhibiting the selection of a valid
irq.

Solution: Don't check for a valid (= already assigned) irq at the point
of calling pnp_resource_change.

Tested successfully on Linux 2.6.11.

Before applying the patch:

May 30 10:50:15 fenrir kernel: pnp: Device 01:01.00 activated.
May 30 10:50:15 fenrir kernel: ALSA sound/isa/cs423x/cs4236.c:325:
isapnp WSS: wss port=0x534, fm port=0x388, sb port=0x220
May 30 10:50:15 fenrir kernel: ALSA sound/isa/cs423x/cs4236.c:327:
isapnp WSS: irq=5, dma1=1, dma2=3
May 30 10:50:15 fenrir kernel: pnp: Device 01:01.02 activated.
May 30 10:50:15 fenrir kernel: ALSA sound/isa/cs423x/cs4236.c:344:
isapnp CTRL: control port=0x120
May 30 10:50:15 fenrir kernel: pnp: Device 01:01.03 activated.
May 30 10:50:15 fenrir kernel: ALSA sound/isa/cs423x/cs4236.c:372:
isapnp MPU: port=0x330, irq=-1
May 30 10:50:15 fenrir kernel: ALSA sound/isa/cs423x/cs4231_lib.c:1053:
cs4231: port = 0x534, id = 0xa
May 30 10:50:15 fenrir kernel: ALSA sound/isa/cs423x/cs4231_lib.c:1059:
CS4231: VERSION (I25) = 0x3
May 30 10:50:15 fenrir kernel: ALSA sound/isa/cs423x/cs4231_lib.c:1128:
CS4231: ext version; rev = 0xeb, id = 0xeb
May 30 10:50:15 fenrir kernel: ALSA sound/isa/cs423x/cs4236_lib.c:300:
CS4236: [0x120] C1 (version) = 0xeb, ext = 0xeb

After applying the patch:

May 30 12:06:46 fenrir kernel: pnp: Device 01:01.00 activated.
May 30 12:06:46 fenrir kernel: ALSA sound/isa/cs423x/cs4236.c:325:
isapnp WSS: wss port=0x534, fm port=0x388, sb port=0x220
May 30 12:06:46 fenrir kernel: ALSA sound/isa/cs423x/cs4236.c:327:
isapnp WSS: irq=5, dma1=1, dma2=3
May 30 12:06:46 fenrir kernel: pnp: Device 01:01.02 activated.
May 30 12:06:46 fenrir kernel: ALSA sound/isa/cs423x/cs4236.c:344:
isapnp CTRL: control port=0x120
May 30 12:06:46 fenrir kernel: pnp: Device 01:01.03 activated.
May 30 12:06:46 fenrir kernel: ALSA sound/isa/cs423x/cs4236.c:371:
isapnp MPU: port=0x330, irq=11
May 30 12:06:46 fenrir kernel: ALSA sound/isa/cs423x/cs4231_lib.c:1053:
cs4231: port = 0x534, id = 0xa
May 30 12:06:46 fenrir kernel: ALSA sound/isa/cs423x/cs4231_lib.c:1059:
CS4231: VERSION (I25) = 0x3
May 30 12:06:46 fenrir kernel: ALSA sound/isa/cs423x/cs4231_lib.c:1128:
CS4231: ext version; rev = 0xeb, id = 0xeb
May 30 12:06:46 fenrir kernel: ALSA sound/isa/cs423x/cs4236_lib.c:300:
CS4236: [0x120] C1 (version) = 0xeb, ext = 0xeb

(note the "irq=11" after applying the patch)

I am not a kernel developer, so I cannot guarantee that my observations
are correct. Please feel free to contact me for further information
and/or if I should have missed something. Please cc: to me if possible.


Regards,

Christoph Schulz
E-Mail: develop@kristov.de