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Fix dashcam detection for whole-disk (superfloppy) SD card formats

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First real-hardware test revealed the connected dashcam's SD card ships
factory-formatted with no partition table - lsblk reports it as a bare
"disk" with an fstype set directly, never as a child "part". The
previous detection logic only matched type=="part", so it silently
missed this real device entirely.

list_usb_storage_partitions() now also matches whole-disk USB devices
that have no children and an fstype set directly on them, in addition
to the existing partition-table case. Verified against a fixture built
from this dashcam's actual `lsblk -J` output.

Co-authored-by: Copilot <[email protected]>
This commit is contained in:
Mathieu Moran
2026-08-08 20:50:45 -04:00
co-authored by Copilot
parent 6d61b70a06
commit acaf1747f3
1 changed files with 20 additions and 7 deletions
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modules/app_dash.py
+20 -7
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@@ -7,12 +7,14 @@ etc. - all common dashcam brands are covered since we just walk the whole
filesystem for video extensions instead of assuming a specific folder name),
then unmounts it again.
Detection is done via `lsblk`, filtering for partitions whose parent disk is
Detection is done via `lsblk`, filtering for volumes whose parent disk is
attached over USB (TRAN == "usb"). This is what actually distinguishes a
plugged-in dashcam/USB stick from the Pi's own storage (the boot/root
partitions are on the onboard SD card, transport "mmc", never "usb") - so
it's safe to run against real hardware without risk of touching the Pi's own
filesystem, regardless of which /dev/sdX letter the kernel happens to assign.
Both real partitions and whole-disk "superfloppy" (no partition table)
layouts are matched - some dashcam SD cards ship factory-formatted that way.
"""
import json
import os
@@ -32,12 +34,19 @@ DEFAULT_DESTINATION = os.path.join(
def list_usb_storage_partitions():
"""Return a list of dicts describing USB-attached storage partitions.
"""Return a list of dicts describing USB-attached storage volumes.
Each dict has: path, fstype, label, size, mountpoint. Only partitions
whose parent disk reports TRAN "usb" are included - this is what makes
the detection brand/device-agnostic (no hardcoded /dev/sda) while still
Each dict has: path, fstype, label, size, mountpoint. Only volumes whose
parent disk reports TRAN "usb" are included - this is what makes the
detection brand/device-agnostic (no hardcoded /dev/sda) while still
being safe (never matches the Pi's own onboard mmc storage).
Includes both real partitions (type "part", the common case) *and*
whole-disk USB devices with an `fstype` set directly on them (type
"disk" but no partition table - a "superfloppy" layout with no MBR/GPT).
Several real dashcam SD cards ship formatted this way straight from the
factory - lsblk reports them as a bare "disk" with an fstype, never as a
child "part", so excluding them would silently miss those cameras.
"""
try:
result = subprocess.run(
@@ -61,7 +70,12 @@ def list_usb_storage_partitions():
def walk(devices, inherited_tran=None):
for device in devices:
tran = device.get("tran") or inherited_tran
if device.get("type") == "part" and tran == "usb":
children = device.get("children") or []
is_partition = device.get("type") == "part"
is_superfloppy_disk = (
device.get("type") == "disk" and not children and device.get("fstype")
)
if tran == "usb" and (is_partition or is_superfloppy_disk):
partitions.append(
{
"path": device.get("path"),
@@ -71,7 +85,6 @@ def list_usb_storage_partitions():
"mountpoint": device.get("mountpoint"),
}
)
children = device.get("children") or []
if children:
walk(children, tran)