Re: [PATCH v3 21/24] drm/rockchip: dw-mipi-dsi: defer probe if panel is not loaded

Sean Paul
2017-01-31T19:21:17Z

On Sun, Jan 29, 2017 at 01:24:41PM +0000, John Keeping wrote:
> This ensures that the output resolution is known before fbcon loads.
>
> Signed-off-by: John Keeping <john@metanate.com>
> ---
> Unchanged in v3
> Unchanged in v2
>
> drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> index f5b15377ef85..5bad92e2370e 100644
> --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> @@ -1176,10 +1176,17 @@ static int dw_mipi_dsi_bind(struct device *dev, struct device *master,
>
> dsi->dsi_host.ops = &dw_mipi_dsi_host_ops;
> dsi->dsi_host.dev = dev;
> - return mipi_dsi_host_register(&dsi->dsi_host);
> + ret = mipi_dsi_host_register(&dsi->dsi_host);
> + if (!ret && !dsi->panel) {
> + mipi_dsi_host_unregister(&dsi->dsi_host);
> + drm_encoder_cleanup(&dsi->encoder);
> + drm_connector_cleanup(&dsi->connector);

Move the host registration up before dw_mipi_dsi_register() to avoid
having to clean up the encoder and connector?

> + ret = -EPROBE_DEFER;
> + }
>
> err_pllref:
> - clk_disable_unprepare(dsi->pllref_clk);
> + if (ret)

I personally think it's cleaner to explicitly goto in the error conditional (or
in this case, the defer conditional) and have a return 0; right before the err_*
labels. Then you don't need to worry about a) checking ret in all of your
cleanups and b) someone adding code above the labels that you don't intend to
run.

Sean

> + clk_disable_unprepare(dsi->pllref_clk);
> return ret;
> }
>
> --
> 2.11.0.197.gb556de5.dirty
>
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--
Sean Paul, Software Engineer, Google / Chromium OS