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Commit f4e0bcf06b9771af04273473592aeeb860ca2816

Authored by Guenter Roeck
Committed by Linus Torvalds
1 parent 5f2e8e2b0b
Exists in master and in 39 other branches 8mp-imx_5.4.70_2.3.0, 8qm-imx_5.4.70_2.3.0, emb_imx_lf-5.15.y, emb_lf-6.1.y, imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, imx_4.1.15_1.0.0_ga, pitx_8mp_lf-5.10.y, rt-smarc-imx_4.1.15_1.0.0_ga, rt_linux_5.15.71, smarc-8m-android-11.0.0_2.0.0, smarc-imx6_4.14.98_2.0.0_ga, smarc-imx6_4.9.88_2.0.0_ga, smarc-imx7_4.14.98_2.0.0_ga, smarc-imx7_4.9.11_1.0.0_ga, smarc-imx7_4.9.88_2.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-imx_4.1.15_1.0.0_ga, smarc-imx_4.9.11_1.0.0_ga, smarc-imx_4.9.51_imx8m_ga, smarc-imx_4.9.88_2.0.0_ga, smarc-m6.0.1_2.1.0-ga, smarc-n7.1.2_2.0.0-ga, smarc-rel_imx_4.1.15_1.2.0_ga, smarc_8m_00d0_imx_4.14.98_2.0.0_ga, smarc_8m_imx_4.14.78_1.0.0_ga, smarc_8m_imx_4.14.98_2.0.0_ga, smarc_8m_imx_4.19.35_1.1.0, smarc_8mm_imx_4.14.78_1.0.0_ga, smarc_8mm_imx_4.14.98_2.0.0_ga, smarc_8mm_imx_4.19.35_1.1.0, smarc_8mm_imx_5.4.24_2.1.0, smarc_8mp_lf-5.10.y, smarc_8mq_imx_5.4.24_2.1.0, smarc_8mq_lf-5.10.y, smarc_imx_lf-5.15.y

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>

Showing 1 changed file with 18 additions and 2 deletions Side-by-side Diff

drivers/hwmon/coretemp.c
Diff comments   View file @ f4e0bcf
... ... @@ -506,7 +506,13 @@
506 506 if (attr_no > MAX_CORE_DATA - 1)
507 507 return -ERANGE;
508 508  
509   - /* Skip if it is a HT core, Not an error */
  509 + /*
  510 + * Provide a single set of attributes for all HT siblings of a core
  511 + * to avoid duplicate sensors (the processor ID and core ID of all
  512 + * HT siblings of a core is the same).
  513 + * Skip if a HT sibling of this core is already online.
  514 + * This is not an error.
  515 + */
510 516 if (pdata->core_data[attr_no] != NULL)
511 517 return 0;
512 518  
513 519  
... ... @@ -763,10 +769,20 @@
763 769 if (pdata->core_data[indx] && pdata->core_data[indx]->cpu == cpu)
764 770 coretemp_remove_core(pdata, &pdev->dev, indx);
765 771  
766   - /* Online the HT version of this core, if any */
  772 + /*
  773 + * If a core is taken offline, but a HT sibling of the same core is
  774 + * still online, register the alternate sibling. This ensures that
  775 + * exactly one set of attributes is provided as long as at least one
  776 + * HT sibling of a core is online.
  777 + */
767 778 for_each_sibling(i, cpu) {
768 779 if (i != cpu) {
769 780 get_core_online(i);
  781 + /*
  782 + * Display temperature sensor data for one HT sibling
  783 + * per core only, so abort the loop after one such
  784 + * sibling has been found.
  785 + */
770 786 break;
771 787 }
772 788 }