drm/v3d: Drop the wait for L2T flush to complete. (51c1b6f9) · Commits · 戴 / test

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: ("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

drivers/gpu/drm/v3d/v3d_gem.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -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. */

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