Re: 2.6.32.1 i915 KMS rmmod failure

From: Jesse Barnes
Date: Wed Dec 16 2009 - 14:51:33 EST


On Wed, 16 Dec 2009 20:08:16 +0100
Krzysztof Halasa <khc@xxxxxxxxx> wrote:

> Hi,
>
> The following sequence causes the machine to hang hard:
> modprobe drm debug=65535
> modprobe i915 modeset=1
> rmmod i915
>
> Linux 2.6.32.1 x86-64, i915 (the machine is a slimline MSI Hetis 915
> barebone), 2 GB RAM etc. Kernel messages captured with a serial
> console. Only analog VGA output connected (no EDID, using a "pro" 5 *
> BNC cable to connect to an old analog monitor). There is
> (unconnected) digital DVI and a TV encoder. Other details available
> on request.
>
> The IRQ happens in intel_pipe_set_base()
>
> DRM_DEBUG("Writing base %08lX %08lX %d %d\n", Start, Offset,
> x, y); I915_WRITE(dspstride, crtc->fb->pitch);
> if (IS_I965G(dev)) {
> ...
> } else {
> I915_WRITE(dspbase, Start + Offset);
> I915_READ(dspbase);
> >>>>>>> IRQ seems to be triggered at this point <<<<<<<
> }
>
> Any ideas?

Seems like we should be disabling everything at unload time rather than
trying to set a new mode... If the dspbase we program isn't mapped
anymore we'd definitely get into trouble.

--
Jesse Barnes, Intel Open Source Technology Center
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