drm/tilcdc: Take crtc modeset lock while updating the crtc clock rate

Take crtc modeset lock while updating the crtc clock rate. To avoid a
race in tilcdc_crtc_update_clk(), we do not want crtc mode to change
while we update crtc clock.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.c b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
index f8892e9ad169..b1ac61eac056 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_drv.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
@@ -184,10 +184,13 @@ static int cpufreq_transition(struct notifier_block *nb,
 {
         struct tilcdc_drm_private *priv = container_of(nb,
                         struct tilcdc_drm_private, freq_transition);
+
         if (val == CPUFREQ_POSTCHANGE) {
                 if (priv->lcd_fck_rate != clk_get_rate(priv->clk)) {
+                        drm_modeset_lock_crtc(priv->crtc, NULL);
                         priv->lcd_fck_rate = clk_get_rate(priv->clk);
                         tilcdc_crtc_update_clk(priv->crtc);
+                        drm_modeset_unlock_crtc(priv->crtc);
                 }
         }