On Fri, May 04, 2012 at 11:29:56AM +0200, Daniel Vetter wrote:
> Chris Wilson dug out a hw erratum saying that there's noise on the
> interrupt line on i945G chips. We also have a bug report from a i945GM
> chip with an sdvo hotplug interrupt storm (and no apparent cause).
>
> Play it safe and disable sdvo hotplug on all i945 variants.
>
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=38442
> Reported-and-tested-by: Dominik Köppl <[email protected]>
> Cc: Chris Wilson <[email protected]>
> Signed-Off-by: Daniel Vetter <[email protected]>
I've just realized that this is a regression that has been introduced in
3.1, when we've enabled sdvo hotplug support with
commit cc68c81aed7d892deaf12d720d5455208e94cd0a
Author: Simon Farnsworth <[email protected]>
Date: Wed Sep 21 17:13:30 2011 +0100
drm/i915: Enable SDVO hotplug interrupts for HDMI and DVI
Cc: [email protected]
-Daniel
> ---
> drivers/gpu/drm/i915/intel_sdvo.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_sdvo.c
> b/drivers/gpu/drm/i915/intel_sdvo.c
> index c330efd..bf6be6c 100644
> --- a/drivers/gpu/drm/i915/intel_sdvo.c
> +++ b/drivers/gpu/drm/i915/intel_sdvo.c
> @@ -1232,8 +1232,14 @@ static bool intel_sdvo_get_capabilities(struct
> intel_sdvo *intel_sdvo, struct in
>
> static int intel_sdvo_supports_hotplug(struct intel_sdvo *intel_sdvo)
> {
> + struct drm_device *dev = intel_sdvo->base.base.dev;
> u8 response[2];
>
> + /* HW Erratum: SDVO Hotplug is broken on all i945G chips, there's noise
> + * on the line. */
> + if (IS_I945G(dev) || IS_I945GM(dev))
> + return false;
> +
> return intel_sdvo_get_value(intel_sdvo, SDVO_CMD_GET_HOT_PLUG_SUPPORT,
> &response, 2) && response[0];
> }
> --
> 1.7.10
>
--
Daniel Vetter
Mail: [email protected]
Mobile: +41 (0)79 365 57 48
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