Re: [RFC v7 1/1] leds: asus-aura-scsi: Add ASUS Aura RGB LED driver for ROG NVMe enclosures

[Lee Jones <lee@kernel.org>]

On Wed, 23 Sep 2026, Liang Haowen wrote:

> ASUS ROG external NVMe enclosures (ROG STRIX Arion, USB 0b05:1932) are
> plain USB mass-storage devices with no HID interface: the Aura LEDs
> hang off an ENE controller driven by vendor SCSI commands on the same
> LUN as the disk. The enclosure has 4 independently addressable LEDs,
> verified on hardware.
> 
> Register a scsi_device_handler matched by INQUIRY (vendor "ROG",
> model "ESD-S1C"); it does not claim the sdev (sd keeps owning the
> disk) and exposes each LED as a multicolor LED class device,
> /sys/class/leds/asus-arion-0-0-0-0::led-0 through led-3. The
> H:C:T:L part of the sdev name keeps the names unique when more than
> one enclosure is connected, with its colons flattened to dashes. The
> color section stays empty, since multicolor LEDs enumerate their
> palette via multi_intensity, and the four identical zones use the
> function name with a "-N" ordinal, as the naming section in
> Documentation/leds/leds-class.rst asks for.
> 
> Protocol: a 16-byte vendor CDB (opcode 0xec, 'A' 'S' signature,
> register index, argument count in cdb[13]). MODE 0x8021 (Static) must
> be written first in every sequence or the device ignores it; colours
> go to 0x8160 + 3 * led and 0x8100 + 3 * led (3 bytes, order R, B, G;
> both tables are written because firmware revisions pull from one or
> the other); APPLY 0x80a0 takes 0x01 to apply and 0xaa to save.
> 
> The CDB cannot go through scsi_execute_cmd(): it sizes the command
> via scsi_command_size(opcode), which maps vendor opcode 0xec to
> 10 bytes, so cdb[13] is dropped and the device silently ignores the
> write (GOOD status, no error). The request is built with
> scsi_alloc_request() instead, which initializes the scsi_cmnd parts a
> passthrough needs (command buffer, lengths, rcu head), with cmd_len
> forced to 16, mirroring what SG_IO does from userspace.
> 
> brightness_set only caches the colour and marks the LED in a per-zone
> dirty mask under a spinlock; led_mc_calc_color_components() runs under
> that lock too, because it writes the shared subled_info array and
> trigger events call led_set_brightness() without the led_access lock
> that serializes sysfs stores. A single work item per zone then
> snapshots the mask and colours and runs one ENE sequence for all
> pending LEDs (MODE, colour slots, APPLY, SAVE). Funneling every
> update through one work item keeps the sequences from interleaving
> between concurrent LED updates and batches multi-LED updates into a
> single APPLY/SAVE. A re-queued run with nothing pending returns
> before touching the device, so it cannot wear the flash with a
> pointless SAVE, and the lock keeps a colour write from being
> reordered after its dirty bit on weakly ordered architectures.
> 
> This is the monolithic out-of-tree version as verified on hardware;
> the Kconfig/Makefile/MAINTAINERS wiring lands with the agreed split
> into a SCSI transport helper and a shared ASUS Aura LED interface.
> 
> Signed-off-by: Liang Haowen <nbg2974@gmail.com>
> ---
>  drivers/leds/rgb/leds-asus-aura-scsi.c | 392 +++++++++++++++++++++++++
>  1 file changed, 392 insertions(+)
>  create mode 100644 drivers/leds/rgb/leds-asus-aura-scsi.c

Many (if not all?) of my review comments from v6 still stand.

I will not be reviewing this submission.

-- 
Lee Jones