From 55f556b1082610ac248b1509dcc03f3a29e8b1eb Mon Sep 17 00:00:00 2001
From: Ben Hutchings <ben@decadent.org.uk>
Date: Tue, 8 Jan 2013 03:25:52 +0000
Subject: [PATCH] radeon, amdgpu: Firmware is required for DRM and KMS on R600
 onward

Bug-Debian: https://bugs.debian.org/607194
Bug-Debian: https://bugs.debian.org/607471
Bug-Debian: https://bugs.debian.org/610851
Bug-Debian: https://bugs.debian.org/627497
Bug-Debian: https://bugs.debian.org/632212
Bug-Debian: https://bugs.debian.org/637943
Bug-Debian: https://bugs.debian.org/649448
Bug-Debian: https://bugs.debian.org/697229
Forwarded: no

radeon requires firmware/microcode for the GPU in all chips, but for
newer chips (apparently R600 'Evergreen' onward) it also expects
firmware for the memory controller and other sub-blocks.

radeon attempts to gracefully fall back and disable some features if
the firmware is not available, but becomes unstable - the framebuffer
and/or system memory may be corrupted, or the display may stay black.

Therefore, perform a basic check for the existence of
/lib/firmware/{radeon,amdgpu} when a device is probed, and abort if it
is missing, except for the pre-R600 case.


Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name radeon-amdgpu-firmware-is-required-for-drm-and-kms-on-r600-onward.patch
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 29 ++++++++++++++++++++++++
 drivers/gpu/drm/radeon/radeon_drv.c     | 30 +++++++++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index de7144b06e9..137244029e2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -38,6 +38,8 @@
 #include <linux/mmu_notifier.h>
 #include <linux/suspend.h>
 #include <linux/cc_platform.h>
+#include <linux/namei.h>
+#include <linux/path.h>
 
 #include "amdgpu.h"
 #include "amdgpu_irq.h"
@@ -1998,6 +2000,28 @@ static void amdgpu_get_secondary_funcs(struct amdgpu_device *adev)
 	}
 }
 
+/* Test that /lib/firmware/amdgpu is a directory (or symlink to a
+ * directory).  We could try to match the udev search path, but let's
+ * keep it simple.
+ */
+static bool amdgpu_firmware_installed(void)
+{
+#if IS_BUILTIN(CONFIG_DRM_AMDGPU)
+	/* It may be too early to tell.  Assume it's there. */
+	return true;
+#else
+	struct path path;
+
+	if (kern_path("/lib/firmware/amdgpu", LOOKUP_DIRECTORY | LOOKUP_FOLLOW,
+		      &path) == 0) {
+		path_put(&path);
+		return true;
+	}
+
+	return false;
+#endif
+}
+
 static int amdgpu_pci_probe(struct pci_dev *pdev,
 			    const struct pci_device_id *ent)
 {
@@ -2072,6 +2096,11 @@ static int amdgpu_pci_probe(struct pci_dev *pdev,
 	}
 #endif
 
+	if (!amdgpu_firmware_installed()) {
+		DRM_ERROR("amdgpu requires firmware installed\n");
+		return -ENODEV;
+	}
+
 	/* Get rid of things like offb */
 	ret = drm_aperture_remove_conflicting_pci_framebuffers(pdev, &amdgpu_kms_driver);
 	if (ret)
diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index 956c72b5aa3..a9ba3782511 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -48,6 +48,8 @@
 #include <drm/drm_probe_helper.h>
 #include <drm/drm_vblank.h>
 #include <drm/radeon_drm.h>
+#include <linux/namei.h>
+#include <linux/path.h>
 
 #include "radeon_drv.h"
 #include "radeon.h"
@@ -288,6 +290,28 @@ MODULE_DEVICE_TABLE(pci, pciidlist);
 
 static const struct drm_driver kms_driver;
 
+/* Test that /lib/firmware/radeon is a directory (or symlink to a
+ * directory).  We could try to match the udev search path, but let's
+ * keep it simple.
+ */
+static bool radeon_firmware_installed(void)
+{
+#if IS_BUILTIN(CONFIG_DRM_RADEON)
+	/* It may be too early to tell.  Assume it's there. */
+	return true;
+#else
+	struct path path;
+
+	if (kern_path("/lib/firmware/radeon", LOOKUP_DIRECTORY | LOOKUP_FOLLOW,
+		      &path) == 0) {
+		path_put(&path);
+		return true;
+	}
+
+	return false;
+#endif
+}
+
 static int radeon_pci_probe(struct pci_dev *pdev,
 			    const struct pci_device_id *ent)
 {
@@ -328,6 +352,12 @@ static int radeon_pci_probe(struct pci_dev *pdev,
 	if (vga_switcheroo_client_probe_defer(pdev))
 		return -EPROBE_DEFER;
 
+	if ((ent->driver_data & RADEON_FAMILY_MASK) >= CHIP_R600 &&
+	    !radeon_firmware_installed()) {
+		DRM_ERROR("radeon kernel modesetting for R600 or later requires firmware installed\n");
+		return -ENODEV;
+	}
+
 	/* Get rid of things like offb */
 	ret = drm_aperture_remove_conflicting_pci_framebuffers(pdev, &kms_driver);
 	if (ret)
-- 
2.30.2