BAD: reproducible lockup with SCSI + SOUND on 2.2 and 2.3: FIXED

[Frank de Lange]

Hi'all again,

Somewhere in the previous century I posted about my struggle with
Linux+SCSI+Sound (see 'BAD: reproducible lockup with SCSI + SOUND on 2.2 and
2.3' Mon, 27 Dec 1999 23:55:42 +0100), but saw no response on the list. I think
I may have found the solution for my - and probably also others - problems.

The problems seem to be caused by the mediocre ISA DMA capabilities of the
Intel Triton I chipset which is used on my (Intel) motherboard. The kernel
already provides a mechanism for working around DMA problems with some VIA
chipsets, so I enabled these workarounds on my system. Since I'm still typing
to the sound of music (no, not the musical) accompanied by the whirr of my
CD-RW it seems to work. Sound is a bit garbled, but at least is does not hang.
A reshuffle in DMA and interrupt priorities might fix the sound garbling (or it
might not), but that is something for a later date and less early hour.

Cheers//Frank

Here's a simple patch (against Linux-2.2.14) for the DMA fix:

*** linux/drivers/pci/quirks.c.org	Wed Jan  5 04:47:10 2000
--- linux/drivers/pci/quirks.c	Wed Jan  5 04:49:50 2000
***************
*** 198,207 ****
  	{ PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_82441,	quirk_passive_release,	0x00 },
  	/*
  	 * Its not totally clear which chipsets are the problematic ones
! 	 * This is the 82C586 variants.
  	 */
  	{ PCI_VENDOR_ID_VIA,	PCI_DEVICE_ID_VIA_82C586_0,	quirk_isa_dma_hangs,	0x00 },
  	{ PCI_VENDOR_ID_VIA,	PCI_DEVICE_ID_VIA_82C596_0,	quirk_isa_dma_hangs,	0x00 },
  };
  
  __initfunc(void pci_quirks_init(void))
--- 198,209 ----
  	{ PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_82441,	quirk_passive_release,	0x00 },
  	/*
  	 * Its not totally clear which chipsets are the problematic ones
! 	 * This is the 82C586 variants. The Intel Triton I chipset seems to
! 	 * have the same problems.
  	 */
  	{ PCI_VENDOR_ID_VIA,	PCI_DEVICE_ID_VIA_82C586_0,	quirk_isa_dma_hangs,	0x00 },
  	{ PCI_VENDOR_ID_VIA,	PCI_DEVICE_ID_VIA_82C596_0,	quirk_isa_dma_hangs,	0x00 },
+ 	{ PCI_VENDOR_ID_INTEL,  PCI_DEVICE_ID_INTEL_82437,      quirk_isa_dma_hangs,    0x00 },
  };
  
  __initfunc(void pci_quirks_init(void))

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