linux-kernel - Re: [PATCH v1 1/1] idma64: Don't try to serve interrupts when device is powered off

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Date: Wed, 20 Mar 2024 18:36:10 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
	dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Vinod Koul <vkoul@...nel.org>, Heiner Kallweit <hkallweit1@...il.com>
Subject: Re: [PATCH v1 1/1] idma64: Don't try to serve interrupts when device
 is powered off

On Wed, Mar 20, 2024 at 06:32:10PM +0200, Andy Shevchenko wrote:
> When iDMA 64-bit device is powered off, the IRQ status register
> is all 1:s. This is never happen in real case and signalling that
> the device is simply powered off. Don't try to serve interrupts
> that are not ours.

..

>  	dev_vdbg(idma64->dma.dev, "%s: status=%#x\n", __func__, status);

Dunno if I actually also need to move this message to after the checks...

> +	/* Since IRQ may be shared, check if DMA controller is powered on */
> +	if (status == GENMASK(31, 0))
> +		return IRQ_NONE;
> +
>  	/* Check if we have any interrupt from the DMA controller */
>  	if (!status)
>  		return IRQ_NONE;

-- 
With Best Regards,
Andy Shevchenko