lkml.org 
[lkml]   [2018]   [Dec]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 4/6] drm/v3d: Drop the wait for L2T flush to complete.
Date
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> (v1, comment requested)
---
drivers/gpu/drm/v3d/v3d_gem.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
index 01e879c71cad..c268c7c79566 100644
--- 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, int core)
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. */
--
2.20.0.rc1
\
 
 \ /
  Last update: 2018-12-03 23:25    [W:0.058 / U:17.456 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site