Re: [PATCH] drm/tilcdc: restore correct display mode and contents on pm resume

From: Rob Clark
Date: Thu Apr 24 2014 - 16:48:55 EST


On Mon, Mar 3, 2014 at 2:08 PM, Felipe Balbi <balbi@xxxxxx> wrote:
> From: Darren Etheridge <detheridge@xxxxxx>
>
> On resume the screen contents were not being restored properly. Looking at
> other DRM drivers it seems a call to drm_helper_resume_force_mode() is needed
> in the resume handler to force restoration of the mode and framebuffer data.
>
> Signed-off-by: Darren Etheridge <detheridge@xxxxxx>

Reviewed-by: Rob Clark <robdclark@xxxxxxxxx>

> ---
> drivers/gpu/drm/tilcdc/tilcdc_drv.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.c b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
> index 171a820..1a5ddfa 100644
> --- a/drivers/gpu/drm/tilcdc/tilcdc_drv.c
> +++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
> @@ -563,6 +563,13 @@ static int tilcdc_pm_resume(struct device *dev)
> if (registers[i].save && (priv->rev >= registers[i].rev))
> tilcdc_write(ddev, registers[i].reg, priv->saved_register[n++]);
>
> + /*
> + * if this call isn't here, the display is blank on return from
> + * suspend. With this call here the contents of the framebuffer
> + * during suspend are restored correctly.
> + */
> + drm_helper_resume_force_mode(ddev);
> +
> drm_kms_helper_poll_enable(ddev);
>
> return 0;
> --
> 1.9.0
>
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