Re: [Sound-open-firmware] [PATCH v4 08/14] ASoC: SOF: Add DSP HW abstraction operations

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

On 2/14/19 7:45 AM, Andy Shevchenko wrote:
> On Wed, Feb 13, 2019 at 04:07:28PM -0600, Pierre-Louis Bossart wrote:
>> From: Liam Girdwood <liam.r.girdwood@linux.intel.com>
>>
>> Add operation pointers that can be called by core to control a wide
>> variety of DSP targets. The DSP HW drivers will fill in these
>> operations.
> 
>> +int snd_sof_pci_update_bits_unlocked(struct snd_sof_dev *sdev, u32 offset,
>> +				     u32 mask, u32 value)
>> +{
>> +	struct pci_dev *pci = to_pci_dev(sdev->dev);
>> +	unsigned int old, new;
> 
>> +	u32 ret = ~0; /* explicit init to remove uninitialized use warnings */
> 
> In case you handle pci_read_config_dword() errors, would you get same warning?
> 
> Something like
> 
> unsigned int old, new;
> int ret;
> 
> ret = pci_read_config_dword(..., &old);
> if (ret)
> 	return -ENXIO;
> 
> ...

will give it a try again, I remember trying when we cleaned-up the code 
but can't recall this part.

I just did a git grep pci_read_config_dword and 99% of the calls don't 
check for any errors. Not an excuse but there isn't a clear pattern here.


> 
> 
> I really don't like such assignments that potentially can shadow a real corner
> cases.

Me neither, we've removed a lot of those assignments that were 
unnecessary. cppcheck was the most useful tool for these local variables.

> 
>> +
>> +	pci_read_config_dword(pci, offset, &ret);
>> +	old = ret;
>> +	dev_dbg(sdev->dev, "Debug PCIR: %8.8x at  %8.8x\n", old & mask, offset);
>> +
> 
>> +	new = (old & (~mask)) | (value & mask);
> 
> (~mask) -> ~mask.

yes, will fix.