bcm27xx: add kernel 5.10 support

[openwrt/staging/chunkeey.git] / target / linux / bcm27xx / patches-5.10 / 950-0167-drm-v3d-Don-t-clear-MMU-control-bits-on-exception.patch

diff --git a/target/linux/bcm27xx/patches-5.10/950-0167-drm-v3d-Don-t-clear-MMU-control-bits-on-exception.patch b/target/linux/bcm27xx/patches-5.10/950-0167-drm-v3d-Don-t-clear-MMU-control-bits-on-exception.patch
new file mode 100644 (file)
index 0000000..19bb220
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.10/950-0167-drm-v3d-Don-t-clear-MMU-control-bits-on-exception.patch
@@ -0,0 +1,34 @@
+From 7372f1f8c151f752aa533eaf2b85ad9b21ec9639 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.org>
+Date: Mon, 11 Nov 2019 14:01:41 +0000
+Subject: [PATCH] drm/v3d: Don't clear MMU control bits on exception
+
+MMU exception conditions are reported in the V3D_MMU_CTRL register as
+write-1-to-clear (W1C) bits. The MMU interrupt handling code clears any
+exceptions, but does so by masking out any other bits and writing the
+result back. There are some important control bits in that register,
+including MMU_ENABLE, so a safer approach is to simply write back the
+value just read unaltered.
+
+This patch doesn't remove the cause of the apparent PTE errors, but it
+does reduce the impact to just an error in the kernel log.
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.org>
+---
+ drivers/gpu/drm/v3d/v3d_irq.c | 5 +----
+ 1 file changed, 1 insertion(+), 4 deletions(-)
+
+--- a/drivers/gpu/drm/v3d/v3d_irq.c
++++ b/drivers/gpu/drm/v3d/v3d_irq.c
+@@ -178,10 +178,7 @@ v3d_hub_irq(int irq, void *arg)
+               };
+               const char *client = "?";
+ 
+-              V3D_WRITE(V3D_MMU_CTL,
+-                        V3D_READ(V3D_MMU_CTL) & (V3D_MMU_CTL_CAP_EXCEEDED |
+-                                                 V3D_MMU_CTL_PT_INVALID |
+-                                                 V3D_MMU_CTL_WRITE_VIOLATION));
++              V3D_WRITE(V3D_MMU_CTL, V3D_READ(V3D_MMU_CTL));
+ 
+               if (v3d->ver >= 41) {
+                       axi_id = axi_id >> 5;