drm/nouveau/tegra: Avoid pulsing reset twice

When the GPU powergate is controlled by a generic power domain provider,
the reset will automatically be asserted and deasserted as part of the
power-ungating procedure.

On some Jetson TX2 boards, doing an additional assert and deassert of
the GPU outside of the power-ungate procedure can cause the GPU to go
into a bad state where the memory interface can no longer access system
memory.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c

@@ -52,18 +52,18 @@ nvkm_device_tegra_power_up(struct nvkm_device_tegra *tdev)
 	clk_set_rate(tdev->clk_pwr, 204000000);
 	udelay(10);
 
-	reset_control_assert(tdev->rst);
-	udelay(10);
-
 	if (!tdev->pdev->dev.pm_domain) {
+		reset_control_assert(tdev->rst);
+		udelay(10);
+
 		ret = tegra_powergate_remove_clamping(TEGRA_POWERGATE_3D);
 		if (ret)
 			goto err_clamp;
 		udelay(10);
-	}
 
-	reset_control_deassert(tdev->rst);
-	udelay(10);
+		reset_control_deassert(tdev->rst);
+		udelay(10);
+	}
 
 	return 0;