Martin Peres bf6546b421 drm/nouveau/fan: rewrite the fan tachometer driver to get more precision, faster
The previous driver waited for 250ms to accumulate data. This version times a
complete fan rotation and extrapolates to RPM.

The fan rotational speed should now be read in less than 250ms (worst case)
and usually in less 50ms.

Signed-off-by: Martin Peres <martin.peres@labri.fr>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2012-10-03 13:13:14 +10:00
..
2012-07-19 22:50:28 -04:00
2012-07-19 22:50:28 -04:00
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2012-08-24 09:38:40 +10:00
2012-07-19 22:50:55 -04:00
2012-07-19 22:50:55 -04:00
2012-07-19 22:50:55 -04:00
2012-07-19 22:50:55 -04:00
2012-02-29 10:18:29 +00:00

************************************************************
* For the very latest on DRI development, please see:      *
*     http://dri.freedesktop.org/                          *
************************************************************

The Direct Rendering Manager (drm) is a device-independent kernel-level
device driver that provides support for the XFree86 Direct Rendering
Infrastructure (DRI).

The DRM supports the Direct Rendering Infrastructure (DRI) in four major
ways:

    1. The DRM provides synchronized access to the graphics hardware via
       the use of an optimized two-tiered lock.

    2. The DRM enforces the DRI security policy for access to the graphics
       hardware by only allowing authenticated X11 clients access to
       restricted regions of memory.

    3. The DRM provides a generic DMA engine, complete with multiple
       queues and the ability to detect the need for an OpenGL context
       switch.

    4. The DRM is extensible via the use of small device-specific modules
       that rely extensively on the API exported by the DRM module.


Documentation on the DRI is available from:
    http://dri.freedesktop.org/wiki/Documentation
    http://sourceforge.net/project/showfiles.php?group_id=387
    http://dri.sourceforge.net/doc/

For specific information about kernel-level support, see:

    The Direct Rendering Manager, Kernel Support for the Direct Rendering
    Infrastructure
    http://dri.sourceforge.net/doc/drm_low_level.html

    Hardware Locking for the Direct Rendering Infrastructure
    http://dri.sourceforge.net/doc/hardware_locking_low_level.html

    A Security Analysis of the Direct Rendering Infrastructure
    http://dri.sourceforge.net/doc/security_low_level.html