2010-06-04 08:00:23

by Jeff Chua

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Subject: Commit cfecde435dda78248d6fcdc424bed68d5db6be0b turns screen blank



The following commit causes screen to become blank. Upon boot up, screen
becomes blank (monitor can't sync to pc) with i915 compiled in the
kernel. With i915 as module, system boots up fine, but becomes blank as
soon as the module is loaded.

Reverting it solves the problem. Problem only happens only Dell Optiplex
780 with external LCD. But, works fine on Lenovo X201s internal LCD.


Thanks,
Jeff

commit cfecde435dda78248d6fcdc424bed68d5db6be0b
Author: Carl Worth <[email protected]>
Date: Thu Apr 8 23:31:57 2010 -0700

drm/i915: Don't enable pipe/plane/VCO early (wait for DPMS on).

The existing code handling the DPMS ON event is much more careful to
ensure that these registers are enabled according to strict sequencing
requirements. Enabling these early in mode_set simply defeats that.

Signed-off-by: Carl Worth <[email protected]>
Signed-off-by: Eric Anholt <[email protected]>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3ee68bc..243dfb8 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3463,11 +3463,6 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc,
pipeconf &= ~PIPEACONF_DOUBLE_WIDE;
}

- dspcntr |= DISPLAY_PLANE_ENABLE;
- pipeconf |= PIPEACONF_ENABLE;
- dpll |= DPLL_VCO_ENABLE;
-
-
/* Disable the panel fitter if it was on our pipe */
if (!HAS_PCH_SPLIT(dev) && intel_panel_fitter_pipe(dev) == pipe)
I915_WRITE(PFIT_CONTROL, 0);


2010-06-04 15:27:50

by Nick Bowler

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Subject: Re: Commit cfecde435dda78248d6fcdc424bed68d5db6be0b turns screen blank

On 16:00 Fri 04 Jun , Jeff Chua wrote:
> The following commit causes screen to become blank. Upon boot up, screen
> becomes blank (monitor can't sync to pc) with i915 compiled in the
> kernel. With i915 as module, system boots up fine, but becomes blank as
> soon as the module is loaded.
>
> Reverting it solves the problem. Problem only happens only Dell Optiplex
> 780 with external LCD. But, works fine on Lenovo X201s internal LCD.

> commit cfecde435dda78248d6fcdc424bed68d5db6be0b

I imagine this is the same as the problem reported here:

http://lkml.org/lkml/2010/6/2/249

--
Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/)

2010-06-04 17:52:07

by Jeff Chua

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Subject: Re: Commit cfecde435dda78248d6fcdc424bed68d5db6be0b turns screen blank

On Fri, Jun 4, 2010 at 11:27 PM, Nick Bowler <[email protected]> wrote:
> On 16:00 Fri 04 Jun ? ? , Jeff Chua wrote:
>> The following commit causes screen to become blank. Upon boot up, screen
>> becomes blank (monitor can't sync to pc) with i915 compiled in the
>> kernel. With i915 as module, system boots up fine, but becomes blank as
>> soon as the module is loaded.
>>
>> Reverting it solves the problem. Problem only happens only Dell Optiplex
>> 780 with external LCD. But, works fine on Lenovo X201s internal LCD.
>
>> commit cfecde435dda78248d6fcdc424bed68d5db6be0b
>
> I imagine this is the same as the problem reported here:
>
> ?http://lkml.org/lkml/2010/6/2/249
>

Nick,

That right. It's the same problem.

Thanks,
Jeff