The `[[gnu::packed]]` attribute apparently lowered the required
alignment of the structs, which caused the compiler to generate two
1 byte loads/stores on RISC-V. This caused the kernel to read/write
incorrect values, as the device only seems to accept 2 byte operations.
Following 77441079dd, the code in Kernel/Devices/HID/MouseDevice.cpp
is used by both USB and PS2 rodents. Make sure not to emit misleading
debug messages that could suggest that a USB mouse is a PS/2 one.
There's no need to have separate syscall for this kind of functionality,
as we can just have a device node in /dev, called "beep", that allows
writing tone generation packets to emulate the same behavior.
In addition to that, we remove LibC sysbeep function, as this function
was never being used by any C program nor it was standardized in any
way.
Instead, we move the userspace implementation to LibCore.
A bit old but a relatively uncomplicated device capable of outputting
1920x1080 video with 32-bit color. Tested with a Voodoo 3 3000 16MB
PCI card. Resolution switching from DisplaySettings also works.
If the requested mode contains timing information, it is used directly.
Otherwise, display timing values are selected from the EDID. First the
detailed timings are checked, and then standard and established
timings for which there is a matching DMT mode. The driver does not
(yet) read the actual EDID, so the generic EDID in DisplayConnector now
includes a set of common display modes to make this work.
The driver should also be compatible with the Voodoo Banshee, 4 and 5
but I don't have these cards to test this with. The PCI IDs of these
cards are included as a commented line in case someone wants to give it
a try.
This view is really nice to check flags, but when clearing them we must
make sure that we only ever try to set 1 bit at a time, which makes
setting bits through the structured view a footgun, as that fetches,
ors in and then sets, potentially resetting other flags.
Simplify core methods in the VirtIO bus handling code by ensuring proper
error propagation. This makes initialization of queues, handling changes
in device configuration, and other core patterns more readable as well.
It also allows us to remove the obnoxious pattern of checking for
boolean "success" and if we get false answer then returning an actual
errno code.
The VirtIO specification defines many types of devices with different
purposes, and it also defines 3 possible transport mediums where devices
could be connected to the host machine.
We only care about the PCIe transport, but this commit puts the actual
foundations for supporting the lean MMIO transport too in the future.
To ensure things are kept abstracted but still functional, the VirtIO
transport code is responsible for what is deemed as related to an actual
transport type - allocation of interrupt handlers and tinkering with low
level transport-related registers, etc.
Userspace initially didn't have any sort of mechanism to handle
device hotplug (either removing or inserting a device).
This meant that after a short term of scanning all known devices, by
fetching device events (DeviceEvent packets) from /dev/devctl, we
basically never try to read it again after SystemServer initialization
code.
To accommodate hotplug needs, we change SystemServer by ensuring it will
generate a known set of device nodes at their location during the its
main initialization code. This includes devices like /dev/mem, /dev/zero
and /dev/full, etc.
The actual responsible userspace program to handle hotplug events is a
new userspace program called DeviceMapper, with following key points:
- Its current task is to to constantly read the /dev/devctl device node.
Because we already created generic devices, we only handle devices
that are dynamically-generated in nature, like storage devices, audio
channels, etc.
- Since dynamically-generated device nodes could have an infinite minor
numbers, but major numbers are decoded to a device type, we create an
internal registry based on two structures - DeviceNodeFamily, and
RegisteredDeviceNode. DeviceNodeFamily objects are attached in the
main logic code, when handling a DeviceEvent device insertion packet.
A DeviceNodeFamily object has an internal HashTable to hold objects of
RegisteredDeviceNode class.
- Because some device nodes could still share the same major number (TTY
and serial TTY devices), we have two modes of allocation - limited
allocation (so a range is defined for a major number), or infinite
range. Therefore, two (or more) separate DeviceNodeFamily objects can
can exist albeit sharing the same major number, but they are required
to allocate from a different minor numbers' range to ensure there are
no collisions.
- As for KCOV, we handle this device differently. In case the user
compiled the kernel with such support - this happens to be a singular
device node that we usually don't need, so it's dynamically-generated
too, and because it has only one instance, we don't register it in our
internal registry to not make it complicated needlessly.
The Kernel code is modified to allow proper blocking in case of no
events in the DeviceControlDevice class, because otherwise we will need
to poll periodically the device to check if a new event is available,
which would waste CPU time for no good reason.
The process could be long gone by the point the async IO request has
completed so hold a weak reference pointer to the requesting Process and
try get a strong reference only when needed.
This patch is necessary because otherwise async IO requests can hold
Process objects long after they were terminated, which would make it
impossible to perform certain tasks in the system, like killing all user
processes during the shutdown procedure.
Previously we would set the KeyCode correctly to the appropriate
extended keys values, like Home and End, but keep the code point of the
original keys, like 1, 2, 3, etc. Because of this, the keys would just
print the original keys, instead of behaving like the extended ones.
Shadow doorbell feature was added in the NVMe spec to improve
the performance of virtual devices.
Typically, ringing a doorbell involves writing to an MMIO register in
QEMU, which can be expensive as there will be a trap for the VM.
Shadow doorbell mechanism was added for the VM to communicate with the
OS when it needs to do an MMIO write, thereby avoiding it when it is
not necessary.
There is no performance improvement with this support in Serenity
at the moment because of the block layer constraint of not batching
multiple IOs. Once the command batching support is added to the block
layer, shadow doorbell support can improve performance by avoiding many
MMIO writes.
Default to old MMIO mechanism if shadow doorbell is not supported.
Introduce a new Struct Doorbell that encapsulates the mmio doorbell
register.
This commit does not introduce any functional changes and it is added
in preparation to adding shadow doorbell support.
This was the root cause of zombie processes showing up randomly and
disappearing after some disk activity, such as running shell commands -
The NVMeIO AsyncBlockDeviceRequest member simply held a pointer to a
Process object, therefore it could keep it alive a for a long time after
it ceased to actually function at all.
Add the device ID for PCI serial port cards that use the WCH CH351
chip. This device has been tested with real hardware where the serial
debug output could succesfully be received.
The driver would crash if it was unable to find an output route, and
subsequently the destruction of controller did not invoke
`GenericInterruptHandler::will_be_destroyed()` because on the level of
`AudioController`, that method is unavailable.
By decoupling the interrupt handling from the controller, we get a new
refcounted class that correctly cleans up after itself :^)
We used to not care about stopping an audio output stream for Intel HDA
since AudioServer would continuously send new buffers to play. Since
707f5ac150 however, that has changed.
Intel HDA now uses interrupts to detect when each buffer was completed
by the device, and uses a simple heuristic to detect whether a buffer
underrun has occurred so it can stop the output stream.
This was tested on Qemu's Intel HDA (Linux x86_64) and a bare metal MSI
Starship/Matisse HD Audio Controller.
This is a preparation before we can create a usable mechanism to use
filesystem-specific mount flags.
To keep some compatibility with userland code, LibC and LibCore mount
functions are kept being usable, but now instead of doing an "atomic"
syscall, they do multiple syscalls to perform the complete procedure of
mounting a filesystem.
The FileBackedFileSystem IntrusiveList in the VFS code is now changed to
be protected by a Mutex, because when we mount a new filesystem, we need
to check if a filesystem is already created for a given source_fd so we
do a scan for that OpenFileDescription in that list. If we fail to find
an already-created filesystem we create a new one and register it in the
list if we successfully mounted it. We use a Mutex because we might need
to initiate disk access during the filesystem creation, which will take
other mutexes in other parts of the kernel, therefore making it not
possible to take a spinlock while doing this.
Otherwise, reading will sometimes fail on the Raspberry Pi.
This is mostly a hack, the spec has some info about how the correct
divisor should be calculated and how we can recover from timeouts.
Namely, we previously forgot to configure the SD Host Controller for
4-bit mode after issuing ACMD6, which caused data transfers to fail on
bare metal.
