From: Alex Deucher <alexander.deucher@amd.com>
Date: Wed, 1 Jun 2016 16:54:33 +0000 (-0400)
Subject: drm/amdgpu: add a delay after ATPX dGPU power off
X-Git-Tag: firefly_0821_release~176^2~4^2~31^2~370
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=8f811d101bd2b1c606b5ee1c3a8bd59a4f48cb8d;p=firefly-linux-kernel-4.4.55.git

drm/amdgpu: add a delay after ATPX dGPU power off

commit f81eb1a349d47694fe1e688336ca1b40ea3e248a upstream.

ATPX dGPU power control requires a 200ms delay between
power off and on.  This should fix dGPU failures on
resume from power off.

Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c
index 5a8fbadbd27b..29adbbe225c4 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c
@@ -10,6 +10,7 @@
 #include <linux/slab.h>
 #include <linux/acpi.h>
 #include <linux/pci.h>
+#include <linux/delay.h>
 
 #include "amdgpu_acpi.h"
 
@@ -256,6 +257,10 @@ static int amdgpu_atpx_set_discrete_state(struct amdgpu_atpx *atpx, u8 state)
 		if (!info)
 			return -EIO;
 		kfree(info);
+
+		/* 200ms delay is required after off */
+		if (state == 0)
+			msleep(200);
 	}
 	return 0;
 }