Alex Deucher d8f60cfc93 drm/radeon/kms: Add support for interrupts on r6xx/r7xx chips (v3)
This enables the use of interrupts on r6xx/r7xx hardware.
Interrupts are implemented via a ring buffer.  The GPU adds
interrupts vectors to the ring and the host reads them off
in the interrupt handler.  The interrupt controller requires
firmware like the CP.  This firmware must be installed and
accessble to the firmware loader for interrupts to function.

MSIs don't seem to work on my RS780.  They work fine on all
my discrete cards.  I'm not sure about other RS780s or
RS880s.  I've disabled MSIs on RS780 and RS880, but it would
probably be worth checking on some other systems.

v2 - fix some checkpatch.pl problems;
     re-read the disp int status reg if we restart the ih;

v3 - remove the irq handler if r600_irq_init() fails;
     remove spinlock in r600_ih_ring_fini();
     move ih rb overflow check to r600_get_ih_wptr();
     move irq ack to separate function;

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2009-12-02 14:00:06 +10:00
..
2009-03-28 20:22:18 -04:00
2009-08-31 09:37:22 +10:00
2009-11-25 12:27:42 -08:00

************************************************************
* 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