From: xi <xizard@enib.fr>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] AMD760MPX: bogus chispset ? (was PROBLEM: sound is stutter, sizzle with lasts kernel releases)
Date: Sat, 12 Jul 2003 05:08:44 +0000 [thread overview]
Message-ID: <3F0F97DC.5090500@enib.fr> (raw)
In-Reply-To: <1057959456.20637.45.camel@dhcp22.swansea.linux.org.uk>
[-- Attachment #1: Type: text/plain, Size: 1568 bytes --]
Alan Cox wrote:
> On Gwe, 2003-07-11 at 22:04, xi wrote:
>
>>And one interesting thing:
>>in the AMD762 datasheet (24462.pdf) page 231 (Recommanded BIOS
>>settings), I can see this: "Numerical Values shown with h or b are
>>preferred settings." ; and AMD recommand this:
>>-> set bits 2 and 1 of register 0x4C to "0b"
>>-> set bits 23 and 3 respectively to "0b" and "1b"
>>
>>I can confirm that these settings works much more better, even if they
>>don't exactly follow PCI specs. And I don't think this is specific to my
>> cards since I have tested others.
>>Furthermore, my AMD762 is revision B1 (just before the last one: C0),
>>and my AMD768 revision is B2, the last one.
>>
>>Would you accept I make a patch which doesn't make any change in these
>>registers at least up to AMD762 revision B1 (ie keeping recommanded
>>values from AMD) ?
>
>
> Lets try the AMD recommended settings. My old doc doesnt seem to have
> those. I'll by happy to trial the patch in -ac and see if it plays up
> the usual suspects for PCI spec violations (tg3 and i2o)
>
Ok, I provide two patchs with different behaviour:
* patch_AMD762_PCI_compliance_set_by_bios.diff : lets the BIOS decide
about PCI configuration
* patch_AMD762_PCI_default_AMD_settings.diff : follow AMD
recommendations but not PCI specs.
Patch are against drivers/pci/quirks.c from 2.4.22-pre4
Regards,
Xavier
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[-- Attachment #2: patch_AMD762_PCI_compliance_set_by_bios.diff --]
[-- Type: text/plain, Size: 1411 bytes --]
--- quirks_original.c 2003-07-12 01:58:17.000000000 +0000
+++ quirks.c 2003-07-12 04:40:57.000000000 +0000
@@ -464,22 +464,23 @@
* Following the PCI ordering rules is optional on the AMD762. I'm not
* sure what the designers were smoking but let's not inhale...
*
- * To be fair to AMD, it follows the spec by default, its BIOS people
- * who turn it off!
+ * In fact, AMD even recommends to don't follow PCI standards
+ * in the section "Recommended BIOS settings" of the datasheet
*/
static void __init quirk_amd_ordering(struct pci_dev *dev)
{
- u32 pcic;
- pci_read_config_dword(dev, 0x4C, &pcic);
- if((pcic&6)!=6)
+ u32 pcic1,pcic2;
+
+ pci_read_config_dword(dev, 0x4C, &pcic1);
+ pci_read_config_dword(dev, 0x84, &pcic2);
+
+ if((pcic1&6)!=6 || (pcic2&(1<<23))!=(1<<23))
{
- pcic |= 6;
- printk(KERN_WARNING "BIOS failed to enable PCI standards compliance, fixing this error.\n");
- pci_write_config_dword(dev, 0x4C, pcic);
- pci_read_config_dword(dev, 0x84, &pcic);
- pcic |= (1<<23); /* Required in this mode */
- pci_write_config_dword(dev, 0x84, pcic);
+ /* The AMD762 doesn't follow PCI standards, but it seems to work better in this mode !
+ In order to be fully PCI standards compliant, we should :
+ set bit 1 and 2 of register 0x4C ; set bit 23 and clear bit 3 of register 0x84 */
+ printk(KERN_WARNING "BIOS didn't enabled PCI standards compliance.\n");
}
}
[-- Attachment #3: patch_AMD762_PCI_default_AMD_settings.diff --]
[-- Type: text/plain, Size: 1146 bytes --]
--- quirks_original.c 2003-07-12 01:58:17.000000000 +0000
+++ quirks.c 2003-07-12 04:44:02.000000000 +0000
@@ -464,23 +464,24 @@
* Following the PCI ordering rules is optional on the AMD762. I'm not
* sure what the designers were smoking but let's not inhale...
*
- * To be fair to AMD, it follows the spec by default, its BIOS people
- * who turn it off!
+ * In fact, AMD even recommends to don't follow PCI standards
+ * in the section "Recommended BIOS settings" of the datasheet
*/
static void __init quirk_amd_ordering(struct pci_dev *dev)
{
u32 pcic;
+
+ printk(KERN_WARNING "Setting AMD recommended values for PCI bus. It isn't fully PCI standards compliant\n");
+
pci_read_config_dword(dev, 0x4C, &pcic);
- if((pcic&6)!=6)
- {
- pcic |= 6;
- printk(KERN_WARNING "BIOS failed to enable PCI standards compliance, fixing this error.\n");
+ pcic &= ~((u32)6);
pci_write_config_dword(dev, 0x4C, pcic);
+
pci_read_config_dword(dev, 0x84, &pcic);
- pcic |= (1<<23); /* Required in this mode */
+ pcic &= ~((u32)(1<<23));
+ pcic |= (1<<3);
pci_write_config_dword(dev, 0x84, pcic);
- }
}
#ifdef CONFIG_X86_IO_APIC
next prev parent reply other threads:[~2003-07-12 3:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <3F0EED9B.4080502@enib.fr>
2003-07-11 17:08 ` AMD760MPX: bogus chispset ? (was PROBLEM: sound is stutter, sizzle with lasts kernel releases) Alan Cox
2003-07-11 21:04 ` xi
2003-07-11 21:37 ` Alan Cox
2003-07-12 5:08 ` xi [this message]
2003-07-13 8:13 ` [PATCH] " Alan Cox
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