Re: [PATCH] i2c: i801: Fix Failed to allocate irq -2147483648 error

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 11/24/2017 02:49 PM, Jean Delvare wrote:
> Hi Hans,
> 
> On Wed, 22 Nov 2017 12:28:17 +0100, Hans de Goede wrote:
>> On Apollo Lake devices the BIOS does not set up IRQ routing for the i801
>> SMBUS controller IRQ, so we end up with dev->irq set to IRQ_NOTCONNECTED.
>>
>> Detect this and do not try to use the irq in this case silencing:
>> i801_smbus 0000:00:1f.1: Failed to allocate irq -2147483648: -107
> 
> Isn't it a BIOS bug?

No, as mentioned in:

>> BugLink: https://communities.intel.com/thread/114759

The BIOS deliberately does not contain IRQ routing issues because some
variants of the Windows driver for this falling over if their is
any IRQ routing set, so this is a "feature" not a bug :|

>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>> ---
>>   drivers/i2c/busses/i2c-i801.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
>> index 9e12a53ef7b8..8eac00efadc1 100644
>> --- a/drivers/i2c/busses/i2c-i801.c
>> +++ b/drivers/i2c/busses/i2c-i801.c
>> @@ -1617,6 +1617,9 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
>>   	/* Default timeout in interrupt mode: 200 ms */
>>   	priv->adapter.timeout = HZ / 5;
>>   
>> +	if (dev->irq == IRQ_NOTCONNECTED)
>> +		priv->features &= ~FEATURE_IRQ;
>> +
>>   	if (priv->features & FEATURE_IRQ) {
>>   		u16 pcictl, pcists;
> 
> Certainly better than returning a cryptic error message, so:
> 
> Reviewed-by: Jean Delvare <jdelvare@suse.de>

Thanks.

> However if this is considered a BIOS bug then a pr_err(FW_BUG...) would
> be good to add IMHO.

See above, that would just replace one error message with another on all
Apollo Lake systems.

Regards,

Hans