brcm2708: update to latest patches from RPi foundation

[openwrt/staging/wigyori.git] / target / linux / brcm2708 / patches-4.19 / 950-0496-drm-v3d-Drop-the-wait-for-L2T-flush-to-complete.patch

diff --git a/target/linux/brcm2708/patches-4.19/950-0496-drm-v3d-Drop-the-wait-for-L2T-flush-to-complete.patch b/target/linux/brcm2708/patches-4.19/950-0496-drm-v3d-Drop-the-wait-for-L2T-flush-to-complete.patch
new file mode 100644 (file)
index 0000000..5a72f9c
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.19/950-0496-drm-v3d-Drop-the-wait-for-L2T-flush-to-complete.patch
@@ -0,0 +1,41 @@
+From 9d8fa62500ae52348d36766e70b49c7508addaf3 Mon Sep 17 00:00:00 2001
+From: Eric Anholt <eric@anholt.net>
+Date: Mon, 3 Dec 2018 14:24:36 -0800
+Subject: [PATCH] drm/v3d: Drop the wait for L2T flush to complete.
+
+According to Dave, once you've started an L2T flush, all L2T accesses
+will be blocked until the flush completes.  This fixes a consistent
+3-4ms stall between the ioctl and running the job, and 3DMMES Taiji
+goes from 27fps to 110fps.
+
+v2: Leave a note about why we don't need to wait for completion.
+
+Signed-off-by: Eric Anholt <eric@anholt.net>
+Fixes: 57692c94dcbe ("drm/v3d: Introduce a new DRM driver for Broadcom V3D V3.x+")
+Reviewed-by: Dave Emett <david.emett@broadcom.com>
+Link: https://patchwork.freedesktop.org/patch/msgid/20181203222438.25417-4-eric@anholt.net
+(cherry picked from commit 51c1b6f9eb3dbdec91b0e3c89f623e634c996bbb)
+---
+ drivers/gpu/drm/v3d/v3d_gem.c | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+--- a/drivers/gpu/drm/v3d/v3d_gem.c
++++ b/drivers/gpu/drm/v3d/v3d_gem.c
+@@ -143,13 +143,13 @@ v3d_invalidate_l2(struct v3d_dev *v3d, i
+ static void
+ v3d_flush_l2t(struct v3d_dev *v3d, int core)
+ {
++      /* While there is a busy bit (V3D_L2TCACTL_L2TFLS), we don't
++       * need to wait for completion before dispatching the job --
++       * L2T accesses will be stalled until the flush has completed.
++       */
+       V3D_CORE_WRITE(core, V3D_CTL_L2TCACTL,
+                      V3D_L2TCACTL_L2TFLS |
+                      V3D_SET_FIELD(V3D_L2TCACTL_FLM_FLUSH, V3D_L2TCACTL_FLM));
+-      if (wait_for(!(V3D_CORE_READ(core, V3D_CTL_L2TCACTL) &
+-                     V3D_L2TCACTL_L2TFLS), 100)) {
+-              DRM_ERROR("Timeout waiting for L2T flush\n");
+-      }
+ }
+ 
+ /* Invalidates the slice caches.  These are read-only caches. */