Eric Anholt cdfbc41f6d drm/i915: Remove IMR masking during interrupt handler, and restart it if needed.
The IMR masking was a technique recommended for avoiding getting stuck with
no interrupts generated again in MSI mode.  It kept new IIR bits from getting
set between the IIR read and the IIR write, which would have otherwise
prevented an MSI from ever getting generated again.  However, this caused a
problem for vblank as the IMR mask would keep the pipe event interrupt from
getting reflected in IIR, even after the IMR mask was brought back down.

Instead, just check the state of IIR after we ack the interrupts we're going
to handle, and restart if we didn't get IIR all the way to zero.

Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2008-11-25 09:27:43 +10:00
..
2008-10-18 07:10:53 +10:00
2008-10-18 07:10:53 +10:00
2008-10-18 07:10:10 +10:00
2008-10-18 07:10:53 +10:00
2008-10-18 07:10:53 +10:00
2008-11-01 09:49:46 -07:00
2008-10-18 07:10:11 +10:00

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