Re: [PATCH 06/10] i2c: i801: Remove not needed check for PCI_COMMAND_INTX_DISABLE

[Jean Delvare <jdelvare@suse.de>]

Hi Heiner,

On Sun, 01 Aug 2021 16:21:08 +0200, Heiner Kallweit wrote:
> do_pci_enable_device() takes care that PCI_COMMAND_INTX_DISABLE
> is cleared if a legacy interrupt is used.

Only if pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin) returned a
non-zero pin, if I read the code correctly. While I can't remember the
context in which I wrote this piece of code, I suppose that pin == 0
was the situation where this test was needed. I mean, the board
designer can legitimately not wire the interrupt pin, and require that
polling is being used, right?

In your favor, I can't find any online kernel log with this message.
However that doesn't mean I'm comfortable removing the safety check.

> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
>  drivers/i2c/busses/i2c-i801.c | 9 +--------
>  1 file changed, 1 insertion(+), 8 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index a6287c520..5b9eebc1c 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -1825,19 +1825,12 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
>  		priv->features &= ~FEATURE_IRQ;
>  
>  	if (priv->features & FEATURE_IRQ) {
> -		u16 pcictl, pcists;
> +		u16 pcists;
>  
>  		/* Complain if an interrupt is already pending */
>  		pci_read_config_word(priv->pci_dev, PCI_STATUS, &pcists);
>  		if (pcists & PCI_STATUS_INTERRUPT)
>  			dev_warn(&dev->dev, "An interrupt is pending!\n");
> -
> -		/* Check if interrupts have been disabled */
> -		pci_read_config_word(priv->pci_dev, PCI_COMMAND, &pcictl);
> -		if (pcictl & PCI_COMMAND_INTX_DISABLE) {
> -			dev_info(&dev->dev, "Interrupts are disabled\n");
> -			priv->features &= ~FEATURE_IRQ;
> -		}
>  	}
>  
>  	if (priv->features & FEATURE_IRQ) {


-- 
Jean Delvare
SUSE L3 Support