Re: Linux 2.6.37-rc6

[Chris Wilson]

On Thu, 16 Dec 2010 18:30:11 +0100, Domenico Andreoli <cavokz@xxxxxxxxx> wrote:
> Hi,
> 
> On Wed, Dec 15, 2010 at 07:10:28PM -0800, ext Linus Torvalds wrote:
> > 
> > Go forth and test. And please do remember to ping bugzilla (or
> > developers) about any regressions you find, whether new or old.
> 
> I have some problem with i945, display remains blank. I also tried
> adding i915.modeset=0 but nothing changed. Machine is well alive and
> responds to basic commands like Ctrl+Alt+F1 and Ctrl+Alt+Del but I have
> not other machine to enter via network.

If i915.modeset=0 doesn't restore the display then something is extremely
fishy. Do you see any console output before the i915.ko is loaded?

> [    1.284262] [drm] Initialized drm 1.1.0 20060810
> [    1.284334] i915 0000:00:02.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
> [    1.485212] vgaarb: device changed decodes: PCI:0000:00:02.0,olddecodes=io+mem,decodes=io+mem:owns=io+mem
> [    1.485642] [drm] initialized overlay support
> [    2.526011] No connectors reported connected with modes
> [    2.526053] [drm] Cannot find any crtc or sizes - going 1024x768

The issue appears to be that no outputs are being detected. I presume that
you have instead a VGA connected to the box and that the regression is in
fact e7dbb2f2. If I'm guessing rightly:

diff --git a/drivers/gpu/drm/i915/intel_crt.c
b/drivers/gpu/drm/i915/intel_crt.c
index 8df5743..14c276e 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -148,7 +148,9 @@ static void intel_crt_mode_set(struct drm_encoder *encoder,
                           dpll_md & ~DPLL_MD_UDI_MULTIPLIER_MASK);
        }
 
-       adpa = ADPA_HOTPLUG_BITS;
+       adpa = 0;
+       if (INTEL_INFO(dev)->gen >= 4)
+               adpa |= ADPA_HOTPLUG_BITS;
        if (adjusted_mode->flags & DRM_MODE_FLAG_PHSYNC)
                adpa |= ADPA_HSYNC_ACTIVE_HIGH;
        if (adjusted_mode->flags & DRM_MODE_FLAG_PVSYNC)

-- 
Chris Wilson, Intel Open Source Technology Centre
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