[PATCH v6 09/16] OMAP2+: UART: Add runtime pm support for omap-serial driver
From: Kevin Hilman <hidden>
Date: 2011-10-13 00:06:43
Also in:
linux-omap, linux-serial
"Govindraj.R" [off-list ref] 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. [...]
quoted hunk ↗ jump to hunk
@@ -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.
quoted hunk ↗ jump to hunk
+ } + 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