Re: [PATCH 00/35] ASoC: Intel: Clenaup SST initialization

["Wasko, Michal" <michal.wasko@linux.intel.com>]

On 8/26/2019 11:57 PM, Pierre-Louis Bossart wrote:

>
>
> On 8/26/19 3:08 PM, Cezary Rojewski wrote:
>> On 2019-08-26 18:51, Pierre-Louis Bossart wrote:
>>>
>>>
>>> On 8/26/19 2:24 AM, Wasko, Michal wrote:
>>>>
>>>> On 8/25/2019 1:06 PM, Cezary Rojewski wrote:
>>>>> 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.
>>>>
>>>> If the driver and FW update will be within the same kernel release 
>>>> then IMHO
>>>> there should be no compatibility problem between those two 
>>>> components, right?
>>>> This way kernel users willing to stick to old FW can stay on older 
>>>> kernel version while
>>>> others can update and receive all the latest FW functionality that 
>>>> was developed and enabled.
>>>
>>> I am not comfortable with precluding a kernel update because of a 
>>> single firmware file. There are all sort of reasons for updating a 
>>> kernel, security, sideband attacks and Android CDD compatibility 
>>> being the most obvious ones.
>>>
The single firmware file will not be a blocker as the driver included in 
updated kernel will support it.
All you have to do is the little effort to re-generate your custom 
topology for the new firmware target.
The entire operation should not be a problem as there are dedicated 
utilities like FDK to do that.

Your statement Pierre suggest that everyone should avoid any functional 
changes in kernel
that are not critical because that would be problematic for others who 
switch from older kernel version.
>>>>
>>>> In terms of FW topology compatibility there is an option to read 
>>>> from topology manifest
>>>> a FW version that it was build for and in  case if it does not 
>>>> match FW version present on
>>>> the platform then print warning that the FW topology binary should 
>>>> be rebuild for current
>>>> FW version (x.x.x.x).
>>>
>>> Can you provide a pointer on how the FW version is embedded in a 
>>> .conf/.tplg file? I see a couple where that information does not 
>>> seem present.
>>>
>>>> The above approach at the end may be less confusing then source 
>>>> code or binary duplication.
>>>
>>
>> Indeed. Our existing topology skips that part of internal .xml and 
>> thus such information is not propagated to kernel.
>>
>> Pierre, how about the binary-duplication - as described above? Btw, 
>> that's not a single firmware file ^)^ We would immediately update all 
>> of them, together with topologies.
>
> I didn't understand how you would select the new firmwares? Some code 
> change needs to happen as well?
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