Bridge kernel

examples/sources/bridge.yaml

@@ -27,4 +27,4 @@ kernel:
   default: linux-generic
   bridge: linux-generic-brg-22.04
   bridge_reasons:
-    - nvidia
+    - drivers

subiquity/models/source.py

@@ -67,7 +67,12 @@ def __attrs_post_init__(self):
 
 
 class BridgeKernelReason(enum.Enum):
-    NVIDIA = "nvidia"
+    # When bridge_reasons contains "drivers", some driver packages are known to
+    # be behind, so we should fall back to the bridge kernel.
+    DRIVERS = "drivers"
+    # When bridge_reasons contains "zfs", we should use the bridge kernel as
+    # the default kernel is not yet known to the kernel team to be sufficiently
+    # stable.
     ZFS = "zfs"
 
 

subiquity/server/controllers/kernel.py

@@ -109,12 +109,15 @@ def _confirmed(self):
             self.app.hub.broadcast(InstallerChannels.BRIDGE_KERNEL_DECIDED)
         self._maybe_set_bridge_kernel(BridgeKernelReason.ZFS, fs_model.uses_zfs())
         if not self.app.base_model.source.search_drivers:
-            self._maybe_set_bridge_kernel(BridgeKernelReason.NVIDIA, False)
+            self._maybe_set_bridge_kernel(BridgeKernelReason.DRIVERS, False)
 
     def _drivers_decided(self):
         drivers_controller = self.app.controllers.Drivers
+        # while the term DRIVERS is used here, only some drivers are expected
+        # to trigger bridge kernel fallback, and only then if DRIVERS is listed
+        # as one of the bridge_reasons.
         self._maybe_set_bridge_kernel(
-            BridgeKernelReason.NVIDIA,
+            BridgeKernelReason.DRIVERS,
             drivers_controller.model.do_install
             and any("nvidia" in driver for driver in drivers_controller.drivers),
         )

subiquity/server/controllers/source.py

@@ -114,8 +114,10 @@ def start(self):
         self.app.hub.subscribe(
             (InstallerChannels.CONFIGURED, "locale"), self._set_locale
         )
-        if self.model.catalog.version != 1:
-            raise Exception("unknown source catalog version")
+        if self.model.catalog.version not in (1, 2):
+            raise Exception(
+                f"unknown source catalog version {self.model.catalog.version}"
+            )
 
     def _set_locale(self):
         current = self.app.base_model.locale.selected_language

subiquity/server/controllers/tests/test_kernel.py

@@ -42,19 +42,19 @@ def n_booleans(*, n):
 
 
 bridge_scenarios = []
-for bridge_zfs, bridge_nvidia, has_zfs, has_nvidia in n_booleans(n=4):
+for bridge_zfs, bridge_drivers, has_zfs, has_drivers in n_booleans(n=4):
     # We consider scenarios for each reason being a reason to choose
     # the kernel and actually discovered.
     bridge_reasons = []
     if bridge_zfs:
         bridge_reasons.append(BridgeKernelReason.ZFS)
-    if bridge_nvidia:
-        bridge_reasons.append(BridgeKernelReason.NVIDIA)
+    if bridge_drivers:
+        bridge_reasons.append(BridgeKernelReason.DRIVERS)
     detected_reasons = []
     if has_zfs:
         detected_reasons.append(BridgeKernelReason.ZFS)
-    if has_nvidia:
-        detected_reasons.append(BridgeKernelReason.NVIDIA)
+    if has_drivers:
+        detected_reasons.append(BridgeKernelReason.DRIVERS)
     for search_drivers, do_install in n_booleans(n=2):
         # Then we consider scenarios where the user chooses whether or
         # not to search for drivers and whether or not to install the
@@ -64,7 +64,7 @@ def n_booleans(*, n):
         use_bridge = False
         if bridge_zfs and has_zfs:
             use_bridge = True
-        if bridge_nvidia and has_nvidia and do_install:
+        if bridge_drivers and has_drivers and do_install:
             use_bridge = True
         bridge_scenarios.append(
             (
@@ -174,7 +174,7 @@ async def test_bridge_options(self, scenario):
 
         if not scenario.search_drivers:
             drivers = []
-        elif BridgeKernelReason.NVIDIA in scenario.detected_reasons:
+        elif BridgeKernelReason.DRIVERS in scenario.detected_reasons:
             drivers = ["something-else", "nvidia-driver"]
         else:
             drivers = ["something-else"]