[Intel-gfx] [PATCH] CHROMIUM: i915: Initialize panel timing registers if VBIOS did not.

[Bryan Freed]

My change tries to detect the lack of initialization by A) finding no VBT,
and B) finding 0 values in these registers.

But what if there is a VBIOS out there that really wants these values to be
0?  I provide for that case by checking for VBT.

Is this a reasonable case?  If not, I have no problem moving the check
to init_vbt_default().

bryan.

On Thu, Oct 7, 2010 at 3:55 PM, Chris Wilson <chris at chris-wilson.co.uk>wrote:

> On Thu, 7 Oct 2010 15:48:14 -0700, Bryan Freed <bfreed at chromium.org>
> wrote:
> > The time between start of the pixel clock and backlight enable is a basic
> > panel timing constraint.  If no VBIOS Table is found, and the Panel Power
> > On/Off registers are found to be 0, assume we are booting without VBIOS
> > initialization and set these registers to something reasonable.
>
> IIRC, the panel sequence registers are meant to be stored in the VBIOS. So
> if we add the parsing of those to the driver and add the defaults to
> init_vbt_default() then we can check whether PP_ON_DELAYS is valid upon
> device init (module load and resume) and fixup in case the BIOS does not.
> -Chris
>
> --
> Chris Wilson, Intel Open Source Technology Centre
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/intel-gfx/attachments/20101007/6f01ef40/attachment.html>