Re: [Fedora-ia64-list] [PATCH] ide controller quirk to correct bad BAR resources

From: Prarit Bhargava <prarit_at_redhat.com>
Date: 2007-02-14 02:51:44
Zhang, Yanmin wrote:
> If ide controllers are at legacy mode, only the 4th BAR
> is needed, so some BIOS initiate other BAR with incorrect
> value. ata/ata_piix calls pci_enable_device on the ide
> controller, which will check BAR resources. If the BAR
> resource values are incorrect, pci_enable_device will fail,
> and ata/ata_piix couldn't attach the ide controller.
>
> Below patch against 2.6.20 creates a quirk to correct the
> bad BAR resources for a special ide controller which is
> popular on tiger-4.
>
>   

If I understand the use of quirks, it is to fix hardware issues that 
cannot be resolved by bios fixes, etc..  ie) real HW problems.  At least 
that's been my feeble understanding.  If I'm wrong on that please 
correct me.

Putting this sort of fix in opens up the kernel to resolving many 
vendors' bios issues within the kernel.

I do understand that this is a special case -- it is unlikely a new bios 
will ship for this box.  The way I see it, a future user of this 
platform will have to build kernels that use the old ide-cd/piix driver 
and/or patch the specific OS they are using with this patch.

Bottom line: I'm not convinced this belongs in the upstream kernel, but 
is a good candidate for Fedora.

P.

> Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
>
> ---
>
> --- linux-2.6.20/arch/ia64/kernel/quirks.c	1970-01-01 08:00:00.000000000 +0800
> +++ linux-2.6.20_fix/arch/ia64/kernel/quirks.c	2007-02-12 23:31:28.000000000 +0800
> @@ -0,0 +1,47 @@
> +/*
> + * This file contains work-arounds for ia64 platform bugs.
> + */
> +#include <linux/pci.h>
> +
> +/*
> + * quirk_intel_ide_controller: If an ide/ata controller is
> + * at legacy mode, BIOS might initiates BAR(bar 0~3 and 5)
> + * with incorrect value. This quirk will reset the incorrect
> + * value to 0.
> + */
> +static void __devinit quirk_intel_ide_controller(struct pci_dev *dev)
> +{
> +	unsigned int pos;
> +	struct resource *res;
> +	int fixed = 0;
> +	u8 tmp8;
> +	u8 mask;
> +
> +	if ((dev->class >> 8) != PCI_CLASS_STORAGE_IDE)
> +		return;
> +
> +	/* TODO: What if one channel is in native mode ... */
> +	pci_read_config_byte(dev, PCI_CLASS_PROG, &tmp8);
> +	mask = (1 << 2) | (1 << 0);
> +	if ((tmp8 & mask) == mask)
> +		return;
> +
> +	for( pos = 0; pos < 6; pos ++ ) {
> +		res = &dev->resource[pos];
> +		if (!(res->flags & (IORESOURCE_IO | IORESOURCE_MEM)))
> +			continue;
> +
> +		if (!res->start && res->end) {
> +			res->start = res->end = 0;
> +			res->flags = 0;
> +			fixed = 1;
> +		}
> +	}
> +	if (fixed)
> +		printk(KERN_WARNING
> +			"PCI device %s: BIOS resource configuration fixed.\n",
> +			pci_name(dev));
> +}
> +
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801DB_11, quirk_intel_ide_controller);
> +
> --- linux-2.6.20/arch/ia64/kernel/Makefile	2007-02-08 15:13:41.000000000 +0800
> +++ linux-2.6.20_fix/arch/ia64/kernel/Makefile	2007-02-12 22:49:39.000000000 +0800
> @@ -33,6 +33,7 @@ obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
>  obj-$(CONFIG_IA64_UNCACHED_ALLOCATOR)	+= uncached.o
>  obj-$(CONFIG_AUDIT)		+= audit.o
>  obj-$(CONFIG_PCI_MSI)		+= msi_ia64.o
> +obj-$(CONFIG_PCI)		+= quirks.o
>  mca_recovery-y			+= mca_drv.o mca_drv_asm.o
>  
>  obj-$(CONFIG_IA64_ESI)		+= esi.o
>
> --
> Fedora-ia64-list mailing list
> Fedora-ia64-list@redhat.com
> https://www.redhat.com/mailman/listinfo/fedora-ia64-list
>
>   
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Received on Wed Feb 14 02:52:24 2007

This archive was generated by hypermail 2.1.8 : 2007-02-14 02:52:53 EST