| Message ID | 20181203222438.25417-4-eric@anholt.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2,1/6] drm/v3d: Document cache flushing ABI. | expand |
On Mon, 3 Dec 2018 at 22:24, Eric Anholt <eric@anholt.net> wrote: > > 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> Reviewed-by: Dave Emett <david.emett@broadcom.com> > 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 >
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. */