Hi Tomi,
Thank you for the patch.
On Wed, Nov 01, 2023 at 11:17:45AM +0200, Tomi Valkeinen wrote:
> Add a helper function, dispc_is_idle(), which returns whether the DSS is
> idle (i.e. is any video port enabled).
>
> For now we add a call to it in the suspend and resume callbacks, and
> print a warning if in either place the DSS is not idle.
Could you please explain here why these checks are needed/useful ? Why
would the dispc not be idle ?
> In the future
> this can be used to detect if the bootloader had enabled the DSS, and
> the driver can act on that.
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/tidss/tidss_dispc.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/gpu/drm/tidss/tidss_dispc.c b/drivers/gpu/drm/tidss/tidss_dispc.c
> index 13db062892e3..a527c28c8833 100644
> --- a/drivers/gpu/drm/tidss/tidss_dispc.c
> +++ b/drivers/gpu/drm/tidss/tidss_dispc.c
> @@ -2603,10 +2603,18 @@ void dispc_vp_setup(struct dispc_device *dispc, u32 hw_videoport,
> dispc_vp_set_color_mgmt(dispc, hw_videoport, state, newmodeset);
> }
>
> +static bool dispc_is_idle(struct dispc_device *dispc)
> +{
> + return REG_GET(dispc, DSS_SYSSTATUS, 9, 9);
> +}
> +
> int dispc_runtime_suspend(struct dispc_device *dispc)
> {
> dev_dbg(dispc->dev, "suspend\n");
>
> + if (!dispc_is_idle(dispc))
> + dev_warn(dispc->dev, "Bad HW state: DSS not idle when suspending");
> +
> dispc->is_enabled = false;
>
> clk_disable_unprepare(dispc->fclk);
> @@ -2620,6 +2628,9 @@ int dispc_runtime_resume(struct dispc_device *dispc)
>
> clk_prepare_enable(dispc->fclk);
>
> + if (!dispc_is_idle(dispc))
> + dev_warn(dispc->dev, "Bad HW state: DSS not idle when resuming");
> +
> if (REG_GET(dispc, DSS_SYSSTATUS, 0, 0) == 0)
> dev_warn(dispc->dev, "DSS FUNC RESET not done!\n");
>
--
Regards,
Laurent Pinchart
