From 74e32e423c96aecb06b03954645c8e12cc9d0997 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Leonardo=20Eug=C3=AAnio?= <lelgenio@disroot.org>
Date: Fri, 18 Oct 2024 00:01:43 -0300
Subject: [PATCH] monolith: fix bluetooth dongle

---
 hosts/monolith/default.nix                    |  9 +++-
 ...b-Fix-regression-with-CSR-controllers.diff | 24 ++++++++++
 pkgs/default.nix                              |  1 +
 pkgs/linux-bluetooth.nix                      | 47 +++++++++++++++++++
 4 files changed, 80 insertions(+), 1 deletion(-)
 create mode 100644 patches/linux/v2-Bluetooth-btusb-Fix-regression-with-CSR-controllers.diff
 create mode 100644 pkgs/linux-bluetooth.nix

diff --git a/hosts/monolith/default.nix b/hosts/monolith/default.nix
index 3350e0d..ff2b193 100644
--- a/hosts/monolith/default.nix
+++ b/hosts/monolith/default.nix
@@ -38,7 +38,14 @@ in
 
   boot.kernelPackages = pkgs.linuxPackages_latest;
 
-  boot.extraModulePackages = with config.boot.kernelPackages; [ zenpower ];
+  boot.extraModulePackages = with config.boot.kernelPackages; [
+    zenpower
+    (pkgs.linux-bluetooth.override {
+      kernel = config.boot.kernelPackages.kernel;
+      patches = [ ../../patches/linux/v2-Bluetooth-btusb-Fix-regression-with-CSR-controllers.diff ];
+    })
+  ];
+
   boot.initrd.kernelModules = [ "amdgpu" ];
   boot.kernelModules = [
     "kvm-amd"
diff --git a/patches/linux/v2-Bluetooth-btusb-Fix-regression-with-CSR-controllers.diff b/patches/linux/v2-Bluetooth-btusb-Fix-regression-with-CSR-controllers.diff
new file mode 100644
index 0000000..ae1adeb
--- /dev/null
+++ b/patches/linux/v2-Bluetooth-btusb-Fix-regression-with-CSR-controllers.diff
@@ -0,0 +1,24 @@
+diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
+index c0b6ef8ee5da..f72218c1037e 100644
+--- a/drivers/bluetooth/btusb.c
++++ b/drivers/bluetooth/btusb.c
+@@ -1366,10 +1366,15 @@ static int btusb_submit_intr_urb(struct hci_dev *hdev, gfp_t mem_flags)
+ 	if (!urb)
+ 		return -ENOMEM;
+ 
+-	/* Use maximum HCI Event size so the USB stack handles
+-	 * ZPL/short-transfer automatically.
+-	 */
+-	size = HCI_MAX_EVENT_SIZE;
++	if (le16_to_cpu(data->udev->descriptor.idVendor)  == 0x0a12 &&
++	    le16_to_cpu(data->udev->descriptor.idProduct) == 0x0001)
++		/* Fake CSR devices don't seem to support sort-transter */
++		size = le16_to_cpu(data->intr_ep->wMaxPacketSize);
++	else
++		/* Use maximum HCI Event size so the USB stack handles
++		 * ZPL/short-transfer automatically.
++		 */
++		size = HCI_MAX_EVENT_SIZE;
+ 
+ 	buf = kmalloc(size, mem_flags);
+ 	if (!buf) {
diff --git a/pkgs/default.nix b/pkgs/default.nix
index b3f1b79..530d1cb 100644
--- a/pkgs/default.nix
+++ b/pkgs/default.nix
@@ -8,4 +8,5 @@ rec {
   emmet-cli = pkgs.callPackage ./emmet-cli.nix { };
   material-wifi-icons = pkgs.callPackage ./material-wifi-icons.nix { };
   gnome-pass-search-provider = pkgs.callPackage ./gnome-pass-search-provider.nix { };
+  linux-bluetooth = pkgs.callPackage ./linux-bluetooth.nix { };
 }
diff --git a/pkgs/linux-bluetooth.nix b/pkgs/linux-bluetooth.nix
new file mode 100644
index 0000000..fbe9660
--- /dev/null
+++ b/pkgs/linux-bluetooth.nix
@@ -0,0 +1,47 @@
+{
+  pkgs,
+  lib,
+  kernel ? pkgs.linuxPackages_latest.kernel,
+  patches ? [],
+}:
+
+pkgs.stdenv.mkDerivation {
+  pname = "bluetooth-kernel-module";
+  inherit (kernel)
+    src
+    version
+    postPatch
+    nativeBuildInputs
+    ;
+
+  inherit patches;
+
+  kernel_dev = kernel.dev;
+  kernelVersion = kernel.modDirVersion;
+
+  modulePath = "drivers/bluetooth";
+
+  buildPhase = ''
+    BUILT_KERNEL=$kernel_dev/lib/modules/$kernelVersion/build
+
+    cp $BUILT_KERNEL/Module.symvers .
+    cp $BUILT_KERNEL/.config        .
+    cp $kernel_dev/vmlinux          .
+
+    make "-j$NIX_BUILD_CORES" modules_prepare
+    make "-j$NIX_BUILD_CORES" M=$modulePath modules
+  '';
+
+  installPhase = ''
+    make \
+      INSTALL_MOD_PATH="$out" \
+      XZ="xz -T$NIX_BUILD_CORES" \
+      M="$modulePath" \
+      modules_install
+  '';
+
+  meta = {
+    description = "Bluetooth kernel module";
+    license = lib.licenses.gpl3;
+  };
+}