[v3,0/4] hwmon (it87): Correct handling for configuration mode

Message

Frank Crawford April 28, 2024, 6:06 a.m. UTC

On various Gigabyte boards, incorrectly entering configuration mode
causes the second Super-IO chip to generate LPC bus access errors.
This was preivously fixed by ensuring that the second chip receives the
code to enter configuration mode before the first chip.

On discussion with people who have access to the specification documents
it was noted that this is wrong, and you should not enter or leave
configuration mode for the second chip, as it is enable during
initialisation and should not be changed.

In particular, this was found to be the case on the Gigabyte X670E Aorus
Master board, where it was reporting a totally wrong chip ID (0x8883)
using the previous method.  This was corrected by not entering
configuration mode, and this has been found to still work with older boards.

---

Changes since v1:
 * renamed the feature to FEAT_NOCONF and macro to has_noconf.
 * reworked patch descriptions to be more explicit about the actions and
   remove any reference to the BIOS.

Changes since v2:
 * rename variable from opened to enabled it87_find().
 * corrected final call to superio_exit() in it87_find().
 * minor update to patch documentation for it87_find() change.

Frank Crawford (4):
  Rename FEAT_CONF_NOEXIT to FEAT_NOCONF as more descriptive of requirement
  Do not enter configuration mode for some chiptypes
  Test for chipset before entering configuration mode
  Remove tests nolonger required

 drivers/hwmon/it87.c | 127 +++++++++++++++++++++----------------------
 1 file changed, 61 insertions(+), 66 deletions(-)