答复: 答复: ????: coherent_ht_mainboard()

[YhLu]

Eric,

CPU0 Link0 is connected to CPU1, and CPU0 Link1 is connected to amd8131.

Before        needs_reset |= ht_setup_chain(PCI_DEV(0, 0x18, 0), 0x80);

The link is 16x800,

After that it change to 16x600,

What's the 0x80 for? Do need to change that 0xa0, because CPU0 link1 is to
amd8131.

Regards

YH



-----邮件原件-----
发件人: ebiederman at lnxi.com [mailto:ebiederman at lnxi.com] 
发送时间: 2004年3月24日 11:28
收件人: YhLu
抄送: Stefan Reinauer; linuxbios at clustermatic.org
主题: Re: 答复: ????: coherent_ht_mainboard()

YhLu <YhLu at tyan.com> writes:

> The optimize_link make 
> The link CPU0 to CPU1:  in CPU0 side(link0) is 16x800 and CPU1 side(link0)
> is 16x800

I don't know if 1Ghz is actually supported between cpus.  AMD never
mentions it, at least I had not seen that it was supported when I
wrote that code.  So I erred on the side of caution and limited things
to what is documented as supported.
 
> but the scan_ht_chain change CPU0 side(link0) is 16x600

An 8131 does not operate reliably at over 600Mhz.  Read the errata.
The 8131 does advertise that it can go at 800Mhz though.

> it must think it is connected to 8111 or something.

I believe these cap come from ht_read_freq_cap.  And they
are explicitly set:

Here is the general version in devices/hypertransport.c.
The amdk8 versions are a little more abbreviated.

static unsigned ht_read_freq_cap(device_t dev, unsigned pos)
{
	/* Handle bugs in valid hypertransport frequency reporting */
	unsigned freq_cap;

	freq_cap = pci_read_config16(dev, pos);
	freq_cap &= ~(1 << HT_FREQ_VENDOR); /* Ignore Vendor HT frequencies
*/

	/* AMD 8131 Errata 48 */
	if ((dev->vendor == PCI_VENDOR_ID_AMD) &&
		(dev->device == PCI_DEVICE_ID_AMD_8131_PCIX)) {
		freq_cap &= ~(1 << HT_FREQ_800Mhz);
	}
	/* AMD 8151 Errata 23 */
	if ((dev->vendor == PCI_VENDOR_ID_AMD) &&
		(dev->device == PCI_DEVICE_ID_AMD_8151_SYSCTRL)) {
		freq_cap &= ~(1 << HT_FREQ_800Mhz);
	}
	/* AMD K8 Unsupported 1Ghz? */
	if ((dev->vendor == PCI_VENDOR_ID_AMD) && (dev->device == 0x1100)) {
		freq_cap &= ~(1 << HT_FREQ_1000Mhz);
	}
	return freq_cap;
}

I hope this helps,

Eric