mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-23 20:50:33 -04:00
2bd89a07db
We currently mutliply the link_bw of the fdi link with the pixel multiplier, which is wrong: The FDI link doesn't suddenly grow more bandwidth. In reality the pixel mutliplication only happens in the PCH, before the pixels are fed into the port. But since we our code treats the uses the target clock after pixels are doubled (tripled, ...) already, we need to correct this. Semantically it's clearer to divide the target clock to get the fdi dotclock instead of multiplying the bw, so do that instead. Note that the target clock is already multiplied by the same factor, so the division will never loose accuracy for the M/N computation. The lane computation otoh used the wrong value, we also need to feed the fdi dotclock to that. Split out on a request from Paulo Zanoni. v2: Also fix the lane computation, it used the target clock to compute the bw requirements, not the fdi dotclock (i.e. adjusted with the pixel multiplier). Since sdvo only uses the pixel multiplier for low-res modes (with a dotclock below 100MHz) we wouldn't ever have rejected a bogus mode, but just used an inefficient fdi config. v3: Amend the commit message to explain better what the change for the fdi lane config computation is all about. Requested by Paulo. Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
************************************************************
* 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