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fix(gamepad/windows): Steam-accepted Deck unit serial un-mangles the controller name

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Steam validates the Deck unit serial's format before accepting it. Our
"PFDK..." serial was REJECTED ("Invalid or missing unit serial number"), so
Steam substituted a hash identity and mangled the displayed name to
"Steam Deck Controllerggg" on every host tested. An 'F'-leading serial passes,
so switch to "FVPF..." — keeps the PunktFunk marker one slot in, still distinct
from a real Deck's "FVZZ..." for the Linux self-detection in
physical_steam_controller_present(). The name now shows a clean "Steam Deck
Controller" with a serial-derived handle (verified on .173).

Also fix the UMDF driver's 0xAE GET_STRING_ATTRIBUTE handler to echo the
requested attribute id faithfully instead of collapsing board-serial (0x00)
requests to unit-serial (0x01). Steam still logs a benign "Deck Controller PCB
Serial# invalid" for the board serial — it validates that against a
Valve-internal format for ANY value, including an empty one (verified) — but
that line does not mangle the name, change the handle, or block promotion.

Applied to both transports: host inject/proto/steam_proto.rs::deck_serial
(Linux gadget/usbip) and the pf-dualsense UMDF driver (Windows), which mirror
each other's serial format.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
Enrico Bühler
2026-07-14 14:21:19 +02:00
parent d8e8529cd7
commit f3b6ccaa7f
3 changed files with 43 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files
packaging/windows/drivers/pf-dualsense/src/lib.rs
+31 -14
View File
@@ -673,21 +673,31 @@ fn deck_feature_reply() -> [u8; 64] {
.unwrap_or(0)
& 0xFF;
let unit_id: u32 = 0x5046_0000 | idx;
let serial = format!("PFDK{unit_id:08X}");
let serial = serial.as_bytes();
// Steam validates the unit serial's PREFIX before accepting it: a "PF"-leading serial is
// REJECTED ("Invalid or missing unit serial number …") and Steam then substitutes a hash and
// MANGLES the displayed name ("Steam Deck Controllerggg"). An 'F'-leading serial passes, so we
// keep our PunktFunk marker one slot in ("FVPF") — still distinct enough for the Linux side's
// physical-Deck self-detection while satisfying Steam's format check. (This, not the build-time
// attributes below, is what un-mangles the name — verified by A/B on .173.)
let unit_serial = format!("FVPF{unit_id:08X}");
let unit_serial = unit_serial.as_bytes();
let mut r = [0u8; 64];
match last[0] {
0x83 => {
// GET_ATTRIBUTES_VALUES: [0x83, 0x2d, then 9x (attr-id, value u32-LE)].
r[0] = 0x83;
r[1] = 0x2D;
// Attribute semantics per SDL's controller_constants.h: 0x04 = FIRMWARE_BUILD_TIME
// and 0x0A = BOOTLOADER_BUILD_TIME are unix timestamps that must look like real build
// dates (the old unit-id-derived junk here was cosmetic; the name mangling was the
// serial prefix). Uniqueness rides the serial.
let attrs: [(u8, u32); 9] = [
(0x01, 0x1205),
(0x02, 0),
(0x0A, unit_id),
(0x04, unit_id ^ 0x5555_5555),
(0x09, 0x2E),
(0x0B, 0x0FA0),
(0x01, 0x1205), // ATTRIB_PRODUCT_ID
(0x02, 0), // ATTRIB_CAPABILITIES
(0x0A, 0x6408_9000), // ATTRIB_BOOTLOADER_BUILD_TIME (2023-03-08)
(0x04, 0x66A8_C000), // ATTRIB_FIRMWARE_BUILD_TIME (2024-07-30)
(0x09, 0x2E), // ATTRIB_BOARD_REVISION (captured)
(0x0B, 0x0FA0), // ATTRIB_CONNECTION_INTERVAL_IN_US (4 ms)
(0x0D, 0),
(0x0C, 0),
(0x0E, 0),
@@ -700,12 +710,19 @@ fn deck_feature_reply() -> [u8; 64] {
}
}
0xAE => {
// GET_STRING_ATTRIBUTE: [0xAE, len, attr, ascii…].
let attr = if last[2] != 0 { last[2] } else { 0x01 };
// GET_STRING_ATTRIBUTE: [0xAE, len, attr, ascii…]. Steam requests two strings: attr
// 0x00 = ATTRIB_STR_BOARD_SERIAL (the PCB serial) and 0x01 = ATTRIB_STR_UNIT_SERIAL.
// Echo the exact attr requested (last[2]) — the unit serial is the one that matters:
// getting its format right (FVPF…, see above) is what un-mangles the displayed name.
// Steam ALSO validates the PCB serial against a Valve-internal format we don't have a
// real capture of; it logs "Deck Controller PCB Serial# invalid" for ANY value we send
// (including an empty one — verified on .173), but that line is BENIGN: unlike a bad
// unit serial, it does not mangle the name, change the handle, or block promotion. So we
// serve the unit serial for both attrs and accept the log.
r[0] = 0xAE;
r[1] = serial.len() as u8;
r[2] = attr;
r[3..3 + serial.len()].copy_from_slice(serial);
r[1] = unit_serial.len() as u8;
r[2] = last[2];
r[3..3 + unit_serial.len()].copy_from_slice(unit_serial);
}
_ => r.copy_from_slice(&last),
}
@@ -779,7 +796,7 @@ fn on_get_string(request: &Request) -> NTSTATUS {
.map(|v| v.read_u32(OFF_PAD_INDEX))
.unwrap_or(0)
& 0xFF;
format!("PFDK{:08X}", 0x5046_0000u32 | idx)
format!("FVPF{:08X}", 0x5046_0000u32 | idx)
}
_ => "35533AD6E774".into(),
},