Re: [PATCH 0/3] ALSA: scarlett2: Fix 2i2 Gen 4 direct monitor on firmware 2417

["Geoffrey D. Bennett" <g@b4.vu>]

On Thu, May 21, 2026 at 12:49:06AM +0200, Takashi Iwai wrote:
> On Wed, 20 May 2026 22:27:20 +0200,
> Geoffrey D. Bennett wrote:
> > 
> > On Mon, Apr 27, 2026 at 02:20:48PM +0200, Takashi Iwai wrote:
> > > On Sat, 25 Apr 2026 23:07:30 +0200,
> > > Geoffrey D. Bennett wrote:
> > > > 
> > > > Hi Takashi,
> > > > 
> > > > Firmware 2417 for the Scarlett 4th Gen 2i2 moved the direct monitor
> > > > gain parameters, breaking that control's functionality.
> > > > 
> > > > The driver already has per-device scarlett2_config_set tables
> > > > describing each parameter's offset, but only one table per device, so
> > > > there was no way to express "this offset changed at firmware version
> > > > N". This series adds that capability and uses it to fix the 2i2 Gen 4.
> > > > 
> > > > Patches
> > > > -------
> > > > 
> > > > 1/3: Replace the device info's single config_set pointer with a
> > > > config_sets array of {from_firmware_version, config_set} entries, and
> > > > resolve the running config_set at probe time once the firmware version
> > > > has been read. Each device gets a single entry matching its previous
> > > > min_firmware_version (or 0), so this is a no-op preparation step.
> > > > 
> > > > 2/3: Drop the now-redundant min_firmware_version field from
> > > > scarlett2_device_info; config_sets[0].from_firmware_version carries
> > > > the same meaning. No functional change.
> > > > 
> > > > 3/3: Add a second 2i2 Gen 4 config_set with DIRECT_MONITOR_GAIN at the
> > > > new offset, gated on firmware >= 2417. All other offsets are
> > > > unchanged.
> > > > 
> > > > Patch 1 is a prerequisite for patch 3. Patch 2 isn't a strict
> > > > dependency, but it removes a now-redundant field, so patch 3's Cc:
> > > > stable trailer names both 1 and 2 as prereqs by subject (please
> > > > substitute SHAs at apply time). Patch 2 can be dropped from the stable
> > > > backport if you'd prefer.
> > > > 
> > > > Tested
> > > > ------
> > > > 
> > > > Verified on a Scarlett 2i2 4th Gen by writing to Monitor 1 Mix A Input
> > > > 01 and observing with usbmon:
> > > > 
> > > > - Firmware 2128, patched driver:   write targets offset 0x2A0
> > > > - Firmware 2417, patched driver:   write targets offset 0x2A4
> > > > - Firmware 2417, unpatched driver: write targets offset 0x2A0 (bug)
> > > > 
> > > > Regards,
> > > > Geoffrey
> > > > 
> > > > Geoffrey D. Bennett (3):
> > > >   ALSA: scarlett2: Allow selecting config_set by firmware version
> > > >   ALSA: scarlett2: Fold min_firmware_version into config_sets
> > > >   ALSA: scarlett2: Update offsets for 2i2 Gen 4 firmware 2417
> > > 
> > > Applied all to for-next branch now.  Thanks.
> > > 
> > > 
> > > Takashi
> > 
> > Hi Takashi,
> > 
> > This commit is currently queued for 7.2:
> > 
> >   3ca15754b561 ALSA: scarlett2: Update offsets for 2i2 Gen 4 firmware 2417
> > 
> > Users updating to firmware 2417 are hitting broken direct monitor gain
> > controls, so I wanted to ask if there's any chance of it (and its two
> > prerequisite commits) making 7.1 & stable now rather than waiting for
> > the next merge window?
> 
> The changes are simply too large as a fix for *-rc.
> If you can work on a reduced simpler fix, I can merge it for 7.1-rc,
> though.

Thanks, done. I will submit a reduced fix (+29/-4, single commit) in a
moment.

I'm not sure if anything needs to be done wrt the existing fix in
for-next? Do I need to submit a revert of the reduced fix for 7.2? It
doesn't look like it conflicts, but only one is needed.

Regards,
Geoffrey.