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SubjectRe: coretemp: Support for Intel Atom E6XX CPU (TunnelCreek)?
Date
On Monday 27 June 2011 16:41:08 Jean Delvare wrote:
> Hi Alexander,
>
> On Mon, 27 Jun 2011 12:20:51 +0200, Alexander Stein wrote:
> > I have a patch (for v2.6.39) which adds support for Intel Atom E6XX
> > (TunnelCreek) to coretemp. It's merely only adding x86_model 0x26.
>
> You have a patch, great for you. What do you expect if you don't share
> it with us?

If you insist on seeing that patch (for 2.6.39 btw):

diff --git a/Documentation/hwmon/coretemp b/Documentation/hwmon/coretemp
index 25568f8..8fc82b6 100644
--- a/Documentation/hwmon/coretemp
+++ b/Documentation/hwmon/coretemp
@@ -6,7 +6,8 @@ Supported chips:
Prefix: 'coretemp'
CPUID: family 0x6, models 0xe (Pentium M DC), 0xf (Core 2 DC 65nm),
0x16 (Core 2 SC 65nm), 0x17 (Penryn 45nm),
- 0x1a (Nehalem), 0x1c (Atom), 0x1e (Lynnfield)
+ 0x1a (Nehalem), 0x1c (Atom), 0x1e (Lynnfield),
+ 0x26 (Tunnelcreek)
Datasheet: Intel 64 and IA-32 Architectures Software Developer's Manual
Volume 3A: System Programming Guide
http://softwarecommunity.intel.com/Wiki/Mobility/720.htm
diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index 194ca0a..55f0fda 100644
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -173,9 +173,9 @@ static int __devinit adjust_tjmax(struct cpuinfo_x86 *c,
u32 id, struct device *
usemsr_ee = 0;
}

- /* Atom CPUs */
+ /* Atom and TunnelCreek CPUs */

- if (c->x86_model == 0x1c) {
+ if ((c->x86_model == 0x1c) || (c->x86_model == 0x26)) {
usemsr_ee = 0;

host_bridge = pci_get_bus_and_slot(0, PCI_DEVFN(0, 0));
@@ -283,6 +283,7 @@ static int __devinit get_tjmax(struct cpuinfo_x86 *c, u32
id,
return 100000;
case 0x17:
case 0x1c: /* Atom CPUs */
+ case 0x26: /* TunnelCreek CPU */
return adjust_tjmax(c, id, dev);
default:
dev_warn(dev, "CPU (model=0x%x) is not supported yet,"
@@ -361,7 +362,8 @@ static int __devinit coretemp_probe(struct platform_device
*pdev)
* Atoms don't have it either.
*/

- if ((c->x86_model > 0xe) && (c->x86_model != 0x1c)) {
+ if ((c->x86_model > 0xe) && (c->x86_model != 0x1c)
+ && (c->x86_model != 0x26)) {
err = rdmsr_safe_on_cpu(data->id, MSR_IA32_TEMPERATURE_TARGET,
&eax, &edx);
if (err) {
The patch without hunk 2 still stays valid to me for current git master.

> I'm not quite sure what your patch would be doing anyway. Since kernel
> 2.6.35, supported CPU models are detected using the DTS feature flag
> rather than the family and model numbers, so your Atom E6XX should be
> detected just fine.

Those 3 output lines don't seem like the mode is detected.
coretemp coretemp.0: Unable to read TjMax from CPU.
coretemp coretemp.0: CPU (model=0x26) is not supported yet, using default
TjMax of 100C.
coretemp coretemp.0: Unable to read IA32_TEMPERATURE_TARGET MSR

> Note that there was a bug in kernels 2.6.35 to 2.6.39 with regards to
> TjMax guessing, which was fixed by Gunter Roeck with:
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h
> =4f5f71a7abe329bdad81ee6a8e4545054a7cc30a You'll have to update to kernel
> version 2.6.39.2 to get this fix.

Cherry-picking this patch, only reduces the output to those two lines:
coretemp coretemp.0: Unable to read TjMax from CPU.
coretemp coretemp.0: Unable to read IA32_TEMPERATURE_TARGET MSR

> Do you happen to know what CPUs model number 0x26 covers? Do you know
> if this model supports MSR_IA32_TEMPERATURE_TARGET or not? The original
> Atom (model 0x1c) did not.

Both the linux kernel (see above) and the bootloader can't use
MSR_IA32_TEMPERATURE_TARGET, so I guess this model does not support this
feature.
I don't know which models have number 0x26, despite the E6xx.

> > But there are models (e.g. E660 and E660T) with different TjMax, namely
> > 90 degrees C and 110 degrees C. But these different model can't be
> > detected by reading from hardware.
>
> I would appreciate a patch to Documentation/hwmon/coretemp adding the
> known TjMax for these new Atom models.
>
> BTW, is it really impossible to identify these models with a different
> TjMax? Don't the strings "E660" and "E660T" appear in the respective
> "model name" entries in /proc/cpuinfo?

Here's the cpuinfo output. I didnt find anything which would allow this
distinction.

# cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 38
model name : Genuine Intel(R) CPU @ 1.30GHz
stepping : 1
cpu MHz : 1299.936
cache size : 512 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
apicid : 0
initial apicid : 0
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca
cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc
arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3
cx16 xtpr pdcm movbe lahf_lm dts tpr_shadow vnmi
bogomips : 2599.87
clflush size : 64
cache_alignment : 64
address sizes : 32 bits physical, 48 bits virtual
power management:

processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 38
model name : Genuine Intel(R) CPU @ 1.30GHz
stepping : 1
cpu MHz : 1299.936
cache size : 512 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
apicid : 1
initial apicid : 1
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca
cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc
arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3
cx16 xtpr pdcm movbe lahf_lm dts tpr_shadow vnmi
bogomips : 2599.54
clflush size : 64
cache_alignment : 64
address sizes : 32 bits physical, 48 bits virtual
power management:

> > IMO there should be some support to adjust the temperature from
> > userspace. Reading Documentation/hwmon/sysfs-interface only temp1_offset
> > seems to be useable. But I think it is somewhat misleading (especially
> > on multicores), because there must only be one offset.
>
> No, tempN_offset isn't suitable for this case, as it would only shift the
> current temperature and not the limits.
>
> Instead, we could detect the specific CPUs using the model name string
> and adjust TjMax accordingly. And/or we could let the user override
> TjMax through a module parameter (I doubt anyone runs a system with
> CPUs with different TjMax values.)

As there seem to be no model string to distinct, only the module parameter
seems valid to do this change.

Regards,
Alexander


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