Commit 4d20dcd2 authored by Dave Jones's avatar Dave Jones Committed by Dave Jones

[CPUFREQ] Document some oddness in the longhaul driver.

Signed-off-by: default avatarDave Jones <davej@redhat.com>
parent 03f0dd68
...@@ -275,8 +275,17 @@ static int __init longhaul_get_ranges (void) ...@@ -275,8 +275,17 @@ static int __init longhaul_get_ranges (void)
case 4: case 4:
rdmsrl (MSR_VIA_LONGHAUL, longhaul.val); rdmsrl (MSR_VIA_LONGHAUL, longhaul.val);
//TODO: Nehemiah may have borken MaxMHzBR. /*
// need to extrapolate from FSB. * TODO: This code works, but raises a lot of questions.
* - Some Nehemiah's seem to have broken Min/MaxMHzBR's.
* We get around this by using a hardcoded multiplier of 5.0x
* for the minimimum speed, and the speed we booted up at for the max.
* This is done in longhaul_get_cpu_mult() by reading the EBLCR register.
* - According to some VIA documentation EBLCR is only
* in pre-Nehemiah C3s. How this still works is a mystery.
* We're possibly using something undocumented and unsupported,
* But it works, so we don't grumble.
*/
minmult=50; minmult=50;
maxmult=longhaul_get_cpu_mult(); maxmult=longhaul_get_cpu_mult();
......
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