Revision d2e3fce9ddafe689c6f7cb355f23560637e30b9d authored by Ville Syrjälä on 10 November 2020, 21:04:47 UTC, committed by Rodrigo Vivi on 19 November 2020, 06:52:25 UTC
EDID can declare the maximum supported bpc up to 16, and apparently there are displays that do so. Currently we assume 12 bpc is tha max. Fix the assumption and toss in a MISSING_CASE() for any other value we don't expect to see. This fixes modesets with a display with EDID max bpc > 12. Previously any modeset would just silently fail on platforms that didn't otherwise limit this via the max_bpc property. In particular we don't add the max_bpc property to HDMI ports on gmch platforms, and thus we would see the raw max_bpc coming from the EDID. I suppose we could already adjust this to also allow 16bpc, but seeing as no current platform supports that there is little point. Cc: stable@vger.kernel.org Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2632 Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20201110210447.27454-1-ville.syrjala@linux.intel.com Reviewed-by: José Roberto de Souza <jose.souza@intel.com> (cherry picked from commit 2ca5a7b85b0c2b97ef08afbd7799b022e29f192e) Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
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pc87427.rst
Kernel driver pc87427
=====================
Supported chips:
* National Semiconductor PC87427
Prefix: 'pc87427'
Addresses scanned: none, address read from Super I/O config space
Datasheet: No longer available
Author: Jean Delvare <jdelvare@suse.de>
Thanks to Amir Habibi at Candelis for setting up a test system, and to
Michael Kress for testing several iterations of this driver.
Description
-----------
The National Semiconductor Super I/O chip includes complete hardware
monitoring capabilities. It can monitor up to 18 voltages, 8 fans and
6 temperature sensors. Only the fans and temperatures are supported at
the moment, voltages aren't.
This chip also has fan controlling features (up to 4 PWM outputs),
which are partly supported by this driver.
The driver assumes that no more than one chip is present, which seems
reasonable.
Fan Monitoring
--------------
Fan rotation speeds are reported as 14-bit values from a gated clock
signal. Speeds down to 83 RPM can be measured.
An alarm is triggered if the rotation speed drops below a programmable
limit. Another alarm is triggered if the speed is too low to be measured
(including stalled or missing fan).
Fan Speed Control
-----------------
Fan speed can be controlled by PWM outputs. There are 4 possible modes:
always off, always on, manual and automatic. The latter isn't supported
by the driver: you can only return to that mode if it was the original
setting, and the configuration interface is missing.
Temperature Monitoring
----------------------
The PC87427 relies on external sensors (following the SensorPath
standard), so the resolution and range depend on the type of sensor
connected. The integer part can be 8-bit or 9-bit, and can be signed or
not. I couldn't find a way to figure out the external sensor data
temperature format, so user-space adjustment (typically by a factor 2)
may be required.
Computing file changes ...
