drm/i915: disable sdvo hotplug on i945g/gm

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.

Note that this is a regression that has been introduced in 3.1,
when we've enabled sdvo hotplug support with

commit cc68c81aed
Author: Simon Farnsworth <simon.farnsworth@onelan.co.uk>
Date:   Wed Sep 21 17:13:30 2011 +0100

    drm/i915: Enable SDVO hotplug interrupts for HDMI and DVI

Cc: stable@kernel.org
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=38442
Reported-and-tested-by: Dominik Köppl <dominik@devwork.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Daniel Vetter 2012-05-04 11:29:56 +02:00
parent d48b97b403
commit 768b107e4b

View File

@ -1220,8 +1220,14 @@ 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];
}