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device-manager: data-driven driver matching via /etc/devices.csv

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Replace the three hardcoded switch tables (pciDriverForIdentity, hidDriverFor,
usbDriverForIdentity) with an authoritative, human-readable device registry the
manager reads at boot. Matching is most-specific-wins across
base/subclass/prog_if/vendor/device/subsystem/hid, so a precise vendor:device
rule and a generic class rule coexist; an unmatched device is logged, never
guessed. This resolves docs' "matching stays code until the third bus".

- ABI: child_added and DeviceDescriptor gain vendor/device/subsystem; child_added
  gains a bus discriminator (BusKind) so PCI and USB class triples match against
  the right namespace.
- pci-bus reads vendor/device (config 0x00) and subsystem (0x2C, type-0) and
  reports them.
- library/device/registry: freestanding CSV parser + matchDriver() with
  specificity scoring; 5 unit tests wired into `zig build test`.
- etc/devices.csv bundled into the initrd; the kernel serves /etc directly, so
  the manager reads it before any filesystem service is up (fat starts later).
- virtio-gpu: drop the now-redundant post-spawn 1AF4:1050 re-confirm, since the
  registry binds this driver by exact identity.
- Remove the orphaned system/drivers/display driver (unreferenced by build or
  registry).
- docs: new devices-csv.md; device-manager.md "matching stays code" resolved.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KJqSiLLchDUUCoXn5jsiwd
This commit is contained in:
daniel
2026-07-26 16:43:13 +01:00
co-authored by Claude Opus 4.8
parent bf0c3fd3e0
commit 203528c8a7
14 changed files with 645 additions and 245 deletions
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system/drivers/virtio-gpu/virtio-gpu.zig
+5 -14
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@@ -33,11 +33,6 @@ const vg = @import("virtio-gpu-protocol.zig");
/// the compositor in the announce so it packs colours in the surface's byte order.
const display_format_bgrx: u32 = 1;
/// The PCI vendor/device ids of a modern virtio-gpu (Red Hat / virtio; GPU is a
/// virtio-1.0-only device, so the id is always the modern 0x1050 — no legacy variant).
const virtio_vendor: u16 = 0x1AF4;
const virtio_gpu_device: u16 = 0x1050;
/// The scanout resource + shared surface are sized to the *largest* mode we offer; a mode
/// change (V5) re-points the scanout rectangle within it, so the resource, its backing, and
/// the shared surface never churn — and the surface's row stride is always `max_width`, which
@@ -210,19 +205,15 @@ fn initialise(endpoint: ipc.Handle) bool {
return false;
};
// Config space is resource 0. Confirm it really is a virtio-gpu, then enable memory-space
// decode + bus mastering (the device DMAs the ring and backing out of RAM); pci-bus only
// preserves whatever the firmware left, and a secondary display is often left disabled.
// Config space is resource 0. The registry (/etc/devices.csv) bound this driver by the
// exact virtio-gpu identity (vendor 0x1AF4 / device 0x1050), so there is no re-confirm to
// do here any more — map config space and enable memory-space decode + bus mastering (the
// device DMAs the ring and backing out of RAM; pci-bus only preserves whatever the firmware
// left, and a secondary display is often left disabled).
var function = pci.Function.map(device_id, descriptor) orelse {
std.log.info("config-space map failed", .{});
return false;
};
const vendor = function.vendorId();
const dev = function.deviceId();
if (vendor != virtio_vendor or dev != virtio_gpu_device) {
std.log.info("not a virtio-gpu (vendor 0x{x} device 0x{x})", .{ vendor, dev });
return false;
}
function.enableMemoryAndBusMaster();
// Walk the capability list for the virtio common-config and notify structures (V3 needs