[alsa-devel] [PATCH 00/35] ASoC: Intel: Clenaup SST initialization

[Cezary Rojewski]

On 2019-08-24 15:51, Cezary Rojewski wrote:
> On 2019-08-23 23:39, Mark Brown wrote:
>> On Fri, Aug 23, 2019 at 03:12:18PM -0500, Pierre-Louis Bossart wrote:
>>> On 8/23/19 1:44 PM, Cezary Rojewski wrote:
>>
>>>> Wasn't lying about FW version being unreliable. Let's say vendor
>>>> receives quick FW drop with new RCR.. such eng drop may carry invalid
>>>> numbers such as 0.0.0.0..
>>>> In general, I try to avoid relying on FW version whenever possible. It
>>>> can be dumped for debug reasons, true, but to be relied on? Not really.
>>
>>> Goodness, that's really bad. I didn't realize this.
>>
>> At a previous employer I modified our build stamping
>> infrastructure to also include both a timestamp and a serialized
>> build number in the version number since one of my colleagues was
>> fond of sending people prereleases of what he was working on to
>> other people with identical version numbers on different
>> binaries leading to much confusion and checksumming.  You do see
>> a lot of things with those serialized version numbers, especially
>> SVN based projects.
>>
>>>> Personally, I'm against all hardcodes and would simply recommend all
>>>> user to redirect their symlinks when they do switch kernel - along with
>>>> dumping warning/ error message in dmesg. Hardcodes bring problems with
>>>> forward compatibility and that's why host should offload them away to
>>>> FW.
>>
>>> Cezary, I know you are not responsible for all this, but at this 
>>> point if we
>>> (Intel) can't guarantee any sort of interoperability with both 
>>> firmware and
>>> topology we should make it clear that this driver is not recommended 
>>> unless
>>> specific versions of the firmware/topology are used, and as a 
>>> consequence
>>> the typical client distros and desktop/laptop users should use HDaudio
>>> legacy or SOF (for DMICs)
>>
>> Not the most elegent solution but I'm wondering if keeping a copy
>> of the driver as is around and using new locations for the fixed
>> firmware might be the safest way to handle this.  We could have a
>> wrapper which tries to load the newer firmware and uses the fixed
>> driver code if that's there, otherwise tries the old driver with
>> the existing firmware paths.  This is obviously a horror show and
>> leaves the old code sitting there but given the mistakes that
>> have been made the whole situation looks like a house of cards.
>>
> 
> Thanks for the feedback Mark. While I'm not yet on the "SOF will fix 
> this" train, I'm keen to agree to leaving this entirely to SOF if it 
> comes down to us duplicating /skylake.
> 
> However, we are not going to give up that easily. I'll see if some 
> "golden config" hardcodes can't be provided in some legacy.c file which 
> would be fetched if initial setup fails. E.g.: 2cores, 3ssps, 1PAGE_SIZE 
> per trace buffer.. and such. There are quite a few factors to take into 
> consideration though. If "asking" user via dmesg to upgrade the firmware 
> if his/her setup contains obsolete binary is really not an option, then 
> some magic words got to be involved.
> 
> Czarek

On the second thought what if instead of duplicating kernel code, 
binaries would be duplicated?
I.e. rather than targeting /intel/dsp_fw_cnl.bin, _new_ /skylake would 
be expecting /intel/dsp_fw_cnl_release.bin? Same with topology binaries.
In such case, we "only" need to figure out how to propagate new files to 
Linux distos so whenever someone updates their kernel, new binaries are 
already present in their /lib/firmware.

If such option is valid, we can postpone /skylake upgrade till 5.4 
merging window closes and the patches (rough estimation is 150) would 
descend upon alsa-devel in time between 5.4 and 5.5.