HDMI currently stops working after a system suspend/resume cycle.  The
cause is that the mode setting states in hardware gets lost and isn't
restored across the suspend/resume cycle.

The patch adds a very basic suspend/resume support to imx-drm driver,
and calls drm_helper_resume_force_mode() in .resume hook to restore the
mode setting states, so that HDMI can continue working after a system
suspend/resume cycle.

Signed-off-by: Shawn Guo <shawn.guo at freescale.com>
---
Changs since v1:
 - Do not walk through connector->funcs->dpms() but only call
   drm_helper_resume_force_mode() in .resume.

 drivers/staging/imx-drm/imx-drm-core.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/staging/imx-drm/imx-drm-core.c 
b/drivers/staging/imx-drm/imx-drm-core.c
index def8280d7ee6..ab41152089a3 100644
--- a/drivers/staging/imx-drm/imx-drm-core.c
+++ b/drivers/staging/imx-drm/imx-drm-core.c
@@ -696,6 +696,29 @@ static int imx_drm_platform_remove(struct platform_device 
*pdev)
        return 0;
 }

+#ifdef CONFIG_PM_SLEEP
+static int imx_drm_suspend(struct device *dev)
+{
+       struct drm_device *drm_dev = dev_get_drvdata(dev);
+
+       drm_kms_helper_poll_disable(drm_dev);
+
+       return 0;
+}
+
+static int imx_drm_resume(struct device *dev)
+{
+       struct drm_device *drm_dev = dev_get_drvdata(dev);
+
+       drm_helper_resume_force_mode(drm_dev);
+       drm_kms_helper_poll_enable(drm_dev);
+
+       return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(imx_drm_pm_ops, imx_drm_suspend, imx_drm_resume);
+
 static const struct of_device_id imx_drm_dt_ids[] = {
        { .compatible = "fsl,imx-display-subsystem", },
        { /* sentinel */ },
@@ -708,6 +731,7 @@ static struct platform_driver imx_drm_pdrv = {
        .driver         = {
                .owner  = THIS_MODULE,
                .name   = "imx-drm",
+               .pm     = &imx_drm_pm_ops,
                .of_match_table = imx_drm_dt_ids,
        },
 };
-- 
1.9.1

Reply via email to