From a19effb6dbe5bd1be77a6d68eba04dba8993ffeb Mon Sep 17 00:00:00 2001 From: Quanyang Wang Date: Wed, 10 Mar 2021 12:59:45 +0800 Subject: [PATCH] drm: xlnx: zynqmp_dpsub: Call pm_runtime_get_sync before setting pixel clock The Runtime PM subsystem will force the device "fd4a0000.zynqmp-display" to enter suspend state while booting if the following conditions are met: - the usage counter is zero (pm_runtime_get_sync hasn't been called yet) - no 'active' children (no zynqmp-dp-snd-xx node under dpsub node) - no other device in the same power domain (dpdma node has no "power-domains = <&zynqmp_firmware PD_DP>" property) So there is a scenario as below: 1) DP device enters suspend state <- call zynqmp_gpd_power_off 2) zynqmp_disp_crtc_setup_clock <- configurate register VPLL_FRAC_CFG 3) pm_runtime_get_sync <- call zynqmp_gpd_power_on and clear previous VPLL_FRAC_CFG configuration 4) clk_prepare_enable(disp->pclk) <- enable failed since VPLL_FRAC_CFG configuration is corrupted From above, we can see that pm_runtime_get_sync may clear register VPLL_FRAC_CFG configuration and result the failure of clk enabling. Putting pm_runtime_get_sync at the very beginning of the function zynqmp_disp_crtc_atomic_enable can resolve this issue. Signed-off-by: Quanyang Wang Reviewed-by: Laurent Pinchart Signed-off-by: Laurent Pinchart --- drivers/gpu/drm/xlnx/zynqmp_disp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/xlnx/zynqmp_disp.c b/drivers/gpu/drm/xlnx/zynqmp_disp.c index 109d627968ac0..01c6ce7784ddb 100644 --- a/drivers/gpu/drm/xlnx/zynqmp_disp.c +++ b/drivers/gpu/drm/xlnx/zynqmp_disp.c @@ -1452,9 +1452,10 @@ zynqmp_disp_crtc_atomic_enable(struct drm_crtc *crtc, struct drm_display_mode *adjusted_mode = &crtc->state->adjusted_mode; int ret, vrefresh; + pm_runtime_get_sync(disp->dev); + zynqmp_disp_crtc_setup_clock(crtc, adjusted_mode); - pm_runtime_get_sync(disp->dev); ret = clk_prepare_enable(disp->pclk); if (ret) { dev_err(disp->dev, "failed to enable a pixel clock\n"); -- 2.39.5