From: Ben Hutchings <ben@decadent.org.uk>
Date: Tue, 8 Jan 2013 03:25:52 +0000 (+0000)
Subject: radeon: Firmware is required for DRM and KMS on R600 onward
X-Git-Tag: archive/raspbian/4.9.82-1+deb9u3+rpi1_jessie~8^2~121
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/success//%22http:/www.example.com/cgi/success/?a=commitdiff_plain;h=3b328a9fa9c7b031bd004f17b5da10aa78fc359d;p=linux-4.9.git

radeon: Firmware is required for DRM and KMS on R600 onward

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 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-firmware-is-required-for-drm-and-kms-on-r600-onward.patch
---

diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index 30bd4a6a9d46..1f92c549b496 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -43,6 +43,8 @@
 
 #include "drm_crtc_helper.h"
 #include "radeon_kfd.h"
+#include <linux/namei.h>
+#include <linux/path.h>
 
 /*
  * KMS wrapper.
@@ -310,6 +312,29 @@ static struct drm_driver kms_driver;
 
 bool radeon_device_is_virtual(void);
 
+/* 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
+ * assume people take the easy route and install
+ * firmware-linux-nonfree.
+ */
+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_kick_out_firmware_fb(struct pci_dev *pdev)
 {
 	struct apertures_struct *ap;
@@ -347,6 +372,12 @@ 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-amd-graphics.\n");
+		return -ENODEV;
+	}
+
 	/* Get rid of things like offb */
 	ret = radeon_kick_out_firmware_fb(pdev);
 	if (ret)