From: Christoph Schulz <develop@kristov.de> 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) Cc: Jaroslav Kysela <perex@suse.cz> Cc: Takashi Iwai <tiwai@suse.de> Cc: Adam Belay <ambx1@neo.rr.com> Signed-off-by: Andrew Morton <akpm@osdl.org> --- sound/isa/cs423x/cs4236.c | 3 +-- 1 files changed, 1 insertion(+), 2 deletions(-) diff -puN sound/isa/cs423x/cs4236.c~cs4236-irq-handling-fix sound/isa/cs423x/cs4236.c --- 25/sound/isa/cs423x/cs4236.c~cs4236-irq-handling-fix Thu Jun 2 14:21:04 2005 +++ 25-akpm/sound/isa/cs423x/cs4236.c Thu Jun 2 14:21:04 2005 @@ -349,8 +349,7 @@ static int __devinit snd_card_cs4236_pnp pnp_init_resource_table(cfg); if (mpu_port[dev] != SNDRV_AUTO_PORT) pnp_resource_change(&cfg->port_resource[0], mpu_port[dev], 2); - if (mpu_irq[dev] != SNDRV_AUTO_IRQ && mpu_irq[dev] >= 0 && - pnp_irq_valid(pdev, 0)) + if (mpu_irq[dev] != SNDRV_AUTO_IRQ && mpu_irq[dev] >= 0) pnp_resource_change(&cfg->irq_resource[0], mpu_irq[dev], 1); err = pnp_manual_config_dev(pdev, cfg, 0); if (err < 0) _