diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.19/950-0496-drm-v3d-Drop-the-wait-for-L2T-flush-to-complete.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.19/950-0496-drm-v3d-Drop-the-wait-for-L2T-flush-to-complete.patch | 41 |
1 files changed, 41 insertions, 0 deletions
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 index 0000000000..5a72f9c71f --- /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. */ |