diff options
| author | Guenter Roeck <guenter.roeck@ericsson.com> | 2011-05-23 14:05:38 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-23 21:11:14 -0700 |
| commit | f4e0bcf06b9771af04273473592aeeb860ca2816 (patch) | |
| tree | 0cf83331612b1e721b9663a71bfd5f364c49992f | |
| parent | 5f2e8e2b0bf0f3a1819b25f6117a7f20bd15521d (diff) | |
hwmon: (coretemp) Add comments describing the handling of HT CPUs
The coretemp driver provides a single set of device attributes for each
physical core of a HT CPU to avoid duplicate sensors. This
functionality was introduced with commit d883b9f09772 ("hwmon:
(coretemp) Skip duplicate CPU entries").
Commit e40cc4bdfd4b ("x86/hwmon: register alternate sibling upon CPU
removal") extends this functionality to register the HT sibling of a CPU
which is taken offline, to ensure that sensor attributes are provided if
at least one HT sibling of a core is online.
Add comments into the code describing the functionality in some more
detail.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/hwmon/coretemp.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c index a00245eb3fa0..9577c432e77f 100644 --- a/drivers/hwmon/coretemp.c +++ b/drivers/hwmon/coretemp.c @@ -506,7 +506,13 @@ static int create_core_data(struct platform_data *pdata, if (attr_no > MAX_CORE_DATA - 1) return -ERANGE; - /* Skip if it is a HT core, Not an error */ + /* + * Provide a single set of attributes for all HT siblings of a core + * to avoid duplicate sensors (the processor ID and core ID of all + * HT siblings of a core is the same). + * Skip if a HT sibling of this core is already online. + * This is not an error. + */ if (pdata->core_data[attr_no] != NULL) return 0; @@ -763,10 +769,20 @@ static void __cpuinit put_core_offline(unsigned int cpu) if (pdata->core_data[indx] && pdata->core_data[indx]->cpu == cpu) coretemp_remove_core(pdata, &pdev->dev, indx); - /* Online the HT version of this core, if any */ + /* + * If a core is taken offline, but a HT sibling of the same core is + * still online, register the alternate sibling. This ensures that + * exactly one set of attributes is provided as long as at least one + * HT sibling of a core is online. + */ for_each_sibling(i, cpu) { if (i != cpu) { get_core_online(i); + /* + * Display temperature sensor data for one HT sibling + * per core only, so abort the loop after one such + * sibling has been found. + */ break; } } |