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.
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.
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