"Govindraj.R" <govindraj.raja@xxxxxx> writes:
[...]
> Use device_may_wakeup to check whether uart has wakeup capabilities
> and then enable uart runtime usage for the uart.
Curious about what happens when device_may_wakeup() is not set during
device init.
[...]
> @@ -1305,6 +1363,16 @@ static int serial_omap_probe(struct platform_device *pdev)
> up->uart_dma.rx_dma_channel = OMAP_UART_DMA_CH_FREE;
> }
>
> + pm_runtime_use_autosuspend(&pdev->dev);
> + pm_runtime_set_autosuspend_delay(&pdev->dev,
> + OMAP_UART_AUTOSUSPEND_DELAY);
> +
> + pm_runtime_irq_safe(&pdev->dev);
> + if (device_may_wakeup(&pdev->dev)) {
> + pm_runtime_enable(&pdev->dev);
So if device_may_wakeup() is false, runtime PM is not enabled, then...
> + pm_runtime_get_sync(&pdev->dev);
...this get doesn't happen, and the first register access causes a crash.
So either this get isn't needed, because there is no device access in
this path, or this path is broken and needs validation.
> + }
> +
> ui[pdev->id] = up;
> serial_omap_add_console_port(up);
>
> @@ -1312,6 +1380,7 @@ static int serial_omap_probe(struct platform_device *pdev)
> if (ret != 0)
> goto do_release_region;
>
> + pm_runtime_put(&pdev->dev);
...also, this put is not balanced with a corresponding get.
Kevin
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