Kernel: Make i8042 controller initialization sequence more robust

The setting of scan code set sequence is removed, as it's buggy and
could lead the controller to fail immediately when doing self-test
afterwards. We will restore it when we understand how to do so safely.

Allow the user to determine a preferred detection path with a new kernel
command line argument. The defualt option is to check i8042 presence
with an ACPI check and if necessary - an "aggressive" test to determine
i8042 existence in the system.
Also, keep the i8042 controller pointer on the stack, so don't assign
m_i8042_controller member pointer if it does not exist.

1 files changed, 6 insertions, 13 deletions

diff --git a/Kernel/Arch/x86_64/ISABus/I8042Controller.cpp b/Kernel/Arch/x86_64/ISABus/I8042Controller.cpp
index 096ba932b0..f4ceeea04e 100644
--- a/Kernel/Arch/x86_64/ISABus/I8042Controller.cpp
+++ b/Kernel/Arch/x86_64/ISABus/I8042Controller.cpp
@@ -107,23 +107,12 @@ UNMAP_AFTER_INIT ErrorOr<void> I8042Controller::detect_devices()
 
         TRY(do_wait_then_write(I8042Port::Command, I8042Command::ReadConfiguration));
         configuration = TRY(do_wait_then_read(I8042Port::Buffer));
-        TRY(do_wait_then_write(I8042Port::Command, I8042Command::WriteConfiguration));
         configuration &= ~I8042ConfigurationFlag::FirstPS2PortInterrupt;
         configuration &= ~I8042ConfigurationFlag::SecondPS2PortInterrupt;
-
-        // Note: The default BIOS on the QEMU microvm machine type (qboot) doesn't
-        // behave like SeaBIOS, which means it doesn't set first port scan code translation.
-        // However we rely on compatibility feature of the i8042 to send scan codes of set 1.
-        // To ensure that the controller is always outputting correct scan codes, set it
-        // to scan code 2 (because SeaBIOS on regular QEMU machine does this for us) and enable
-        // first port translation to ensure all scan codes are translated to scan code set 1.
         configuration |= I8042ConfigurationFlag::FirstPS2PortTranslation;
-        TRY(do_wait_then_write(I8042Port::Buffer, configuration));
-        TRY(do_wait_then_write(I8042Port::Buffer, I8042Command::SetScanCodeSet));
-        TRY(do_wait_then_write(I8042Port::Buffer, 0x2));
 
-        m_is_dual_channel = (configuration & I8042ConfigurationFlag::SecondPS2PortClock) != 0;
-        dbgln("I8042: {} channel controller", m_is_dual_channel ? "Dual" : "Single");
+        TRY(do_wait_then_write(I8042Port::Command, I8042Command::WriteConfiguration));
+        TRY(do_wait_then_write(I8042Port::Buffer, configuration));
 
         // Perform controller self-test
         TRY(do_wait_then_write(I8042Port::Command, I8042Command::TestPS2Controller));
@@ -134,8 +123,12 @@ UNMAP_AFTER_INIT ErrorOr<void> I8042Controller::detect_devices()
             TRY(do_wait_then_write(I8042Port::Buffer, configuration));
         } else {
             dbgln("I8042: Controller self test failed");
+            return Error::from_errno(EIO);
         }
 
+        m_is_dual_channel = (configuration & I8042ConfigurationFlag::SecondPS2PortClock) != 0;
+        dbgln("I8042: {} channel controller", m_is_dual_channel ? "Dual" : "Single");
+
         // Test ports and enable them if available
         TRY(do_wait_then_write(I8042Port::Command, I8042Command::TestFirstPS2Port));
         auto first_port_test_result = TRY(do_wait_then_read(I8042Port::Buffer));