Attachment 129490 Details for Bug 99766 – drm/i915: Fix DisplayPort Hotplug

[patch] drm/i915: Fix DisplayPort Hotplug

0001-drm-i915-Fix-DisplayPort-Hotplug.patch (text/plain), 2.18 KB, created by Palmer Dabbelt on 2017-02-10 21:16:11 UTC

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Creator: Palmer Dabbelt

Created: 2017-02-10 21:16:11 UTC

Size: 2.18 KB

patch

obsolete

>From fb33835d25af18dfcecb93c24e07610d004698be Mon Sep 17 00:00:00 2001
>From: Palmer Dabbelt <palmer@dabbelt.com>
>Date: Fri, 10 Feb 2017 12:56:28 -0800
>Subject: [PATCH] drm/i915: Fix DisplayPort Hotplug
>
>DisplayPort no longer hotplugs on my machine (a 2014 MacBook Pro
>attached to an ASUS PB287Q).  I believe the problem is that long pulses
>are no longer triggering intel_dp_check_link_status.  I bisected the
>problem down to (7d23e3c37 "drm/i915: Cleaning up intel_dp_hpd_pulse")
>and it appears the only material change there was to remove one of those
>calls.
>
>This commit adds the check_link_status call back in, which causes hotplug to
>work again for me.  I test this via a "xset dpms force off".  Note that this is
>very similar to <https://bugs.freedesktop.org/show_bug.cgi?id=89453>, but it's
>back again.
>
>I've tested this against 4.9, and it applies against the current head.
>
>Here's the commit that triggered the regression:
>
>commit 7d23e3c37bb3fc6952dc84007ee60cb533fd2d5c
>Author: Shubhangi Shrivastava <shubhangi.shrivastava@intel.com>
>Date:   Wed Mar 30 18:05:23 2016 +0530
>
>    drm/i915: Cleaning up intel_dp_hpd_pulse
>
>    Current DP detection has DPCD operations split across
>    intel_dp_hpd_pulse and intel_dp_detect which contains
>    duplicates as well. Also intel_dp_detect is called
>    during modes enumeration as well which will result
>    in multiple dpcd operations. So this patch tries
>    to solve both these by bringing all DPCD operations
>    in one single function and make intel_dp_detect
>    use existing values instead of repeating same steps.
>---
> drivers/gpu/drm/i915/intel_dp.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
>diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>index 0b8e8eb..32ca4be 100644
>--- a/drivers/gpu/drm/i915/intel_dp.c
>+++ b/drivers/gpu/drm/i915/intel_dp.c
>@@ -4831,6 +4831,10 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
> 		      long_hpd ? "long" : "short");
> 
> 	if (long_hpd) {
>+		drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
>+		intel_dp_check_link_status(intel_dp);
>+		drm_modeset_unlock(&dev->mode_config.connection_mutex);
>+
> 		intel_dp->detect_done = false;
> 		return IRQ_NONE;
> 	}
>-- 
>2.10.2
>

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