Patch "drm/radeon: fix asic initialization for virtualized environments" has been added to the 4.4-stable tree

Patch "drm/radeon: fix asic initialization for virtualized environments" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    drm/radeon: fix asic initialization for virtualized environments

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-radeon-fix-asic-initialization-for-virtualized-environments.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 05082b8bbd1a0ffc74235449c4b8930a8c240f85 Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher@amd.com>
Date: Mon, 13 Jun 2016 15:37:34 -0400
Subject: drm/radeon: fix asic initialization for virtualized environments

From: Alex Deucher <alexander.deucher@amd.com>

commit 05082b8bbd1a0ffc74235449c4b8930a8c240f85 upstream.

When executing in a PCI passthrough based virtuzliation environment, the
hypervisor will usually attempt to send a PCIe bus reset signal to the
ASIC when the VM reboots. In this scenario, the card is not correctly
initialized, but we still consider it to be posted. Therefore, in a
passthrough based environemnt we should always post the card to guarantee
it is in a good state for driver initialization.

Ported from amdgpu commit:
amdgpu: fix asic initialization for virtualized environments

Cc: Andres Rodriguez <andres.rodriguez@amd.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/radeon/radeon_device.c |   21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -630,6 +630,23 @@ void radeon_gtt_location(struct radeon_d
 /*
  * GPU helpers function.
  */
+
+/**
+ * radeon_device_is_virtual - check if we are running is a virtual environment
+ *
+ * Check if the asic has been passed through to a VM (all asics).
+ * Used at driver startup.
+ * Returns true if virtual or false if not.
+ */
+static bool radeon_device_is_virtual(void)
+{
+#ifdef CONFIG_X86
+	return boot_cpu_has(X86_FEATURE_HYPERVISOR);
+#else
+	return false;
+#endif
+}
+
 /**
  * radeon_card_posted - check if the hw has already been initialized
  *
@@ -643,6 +660,10 @@ bool radeon_card_posted(struct radeon_de
 {
 	uint32_t reg;
 
+	/* for pass through, always force asic_init */
+	if (radeon_device_is_virtual())
+		return false;
+
 	/* required for EFI mode on macbook2,1 which uses an r5xx asic */
 	if (efi_enabled(EFI_BOOT) &&
 	    (rdev->pdev->subsystem_vendor == PCI_VENDOR_ID_APPLE) &&


Patches currently in stable-queue which might be from alexander.deucher@amd.com are

queue-4.4/drm-radeon-fix-asic-initialization-for-virtualized-environments.patch
queue-4.4/drm-amdgpu-gfx7-fix-broken-condition-check.patch
queue-4.4/drm-dp-mst-always-clear-proposed-vcpi-table-for-port.patch