By enhancing the Framebuffer::Session interface by the new RPC functions
'blit' and 'panning', GUI clients become able to attain tearing-free
output. Two modes of operations are supported.
1. Atomic back-to-front blitting
GUI clients that partially update their user interface like regular
application dialogs, can now implement double buffering by placing
both the back buffer and front buffer within the GUI session's
framebuffer and configuring a view that shows only the front buffer.
The 'blit' operation allows the client to atomically flush pixels
from the back buffer to the front buffer.
2. Atomic buffer flipping
GUI clients that always update all pixels like a media player or
a game can now use the 'panning' feature to atomically redirect the
displayed pixels to a different portion of the GUI session's virtual
frame buffer. The virtual framebuffer always contains two frames,
the displayed one and the next one. Once the next frame is complete,
the client changes the panning position to the portion containing
the next frame.
Issue #5350
Limit the use of Reg_list::for_each that caches a next pointer
of its items to allow destruction of items in its lambda body.
Instead provide an Reg_list::apply function in addition, which
takes a condition lambda to find the matching item, and a lambda
processed on it. In most use-cases where for_each was used, only
one item was searched for. Here we can use apply now., without
the need for a cached pointer, nor too many iterations.
Fixesgenodelabs/genode#5349
Unless nitpicker is used in 'request_framebuffer' mode, it no longer
depends on a periodic timer but merely acts as a broker between capture
clients and GUI clients. Sync signals as delivered to GUI clients are
now wired to Capture::Session::capture_at calls. So the display driver
defines the occurrence of those signals.
Note that sync signals are only delivered while a driver actively calls
'capture_at'. If a driver stops capturing, GUI clients no longer receive
any sync signal. This is a change from the previous situation where GUI
clients could depend on the periodicity of sync signals.
Issue #5347
With this change, a client (i.e., display driver) can register
a wakeup signal handler to be notified on the arrival of new data to
capture. The signal is delivered only when the client has stopped
capturing. The client propagates this condition to the server using
the new 'capture_stopped' RPC call.
This change in principle enables a display driver to suspend its
periodic mode of operation after a few frames without capturing any
new data. As the first driver, the fb_sdl driver has been adapted to
the new protocol. This change not only eliminates the driver's CPU
load when idle, it also reduces the latency of sporadic output
because the response to such GUI updates is no longer bound by a
fixed periodic interval.
Issue #5344
This patch is a preparatory step for relaxing the strictly periodic
operation of fb_sdl. With the new design, the SDL event loop can block
for events while Genode's main entrypoint stays receptive for I/O.
The main entrypoint can interact with the SDL thread by injecting
SDL user events.
The patch also replaces the full-screen clearing and update of the
SDL window by an update of the captured bounding box only. This reduces
the CPU load of fb_sdl when idle. When updating a small part of the
screen (e.g., when moving the mouse only), the load is still rather
heavy though.
Issue #5344
This patch enhances the Capture::Connection::Screen such that the
bounding box of the affected pixels can be tracked by the caller,
which can use this information to adjust its behavior to the
activity/inactivity of the capture server.
Issue #5344
This patch adds the physical screen size as argument to the
Capture::Session::buffer RPC function, which allows drivers to
propagate DPI information to the GUI server. While changing the
the interface, the patch replaces the former use of C++ exceptions
by a result type. The 'Buffer_result' is handled transparently by the
Capture::Connection. The client.h code is now integrated in
connection.h.
Issue #5344
This is a follow-up commit to "gui_session: manage view ID at the client
side", which missed to invalidate the neighbor view of a window but
instead wrongly assigned the (now always valid) view ID 0 as neighbor.
In situations where a window disappears and re-appears (e.g., repeatedly
launching testnit in the wm.run scenario), the new window could not
always be topped.
Issue #5242
The current default session RAM quota of 36 KiB reflects the needs of
the nitpicker GUI server. However, in most commonly used scenarios, a
GUI client connects to nitpicker indirectly via the wm. The low value
worked so far because the wm did not account RAM and cap usage per
client so far but paid out of its own pocket and faithfully forwarded
all resource upgrades to nitpicker.
When adding resource accounting to the wm, the old default value has the
effect that a new client has to repeatedly attempt the session creation -
each time offering sligthly more session quota - until both nitpicker and
the wm are satisfied.
By roughly doubling the default to 80 KiB, a wm client immediately
succeeds with opening a GUI session without repeated attempts.
By specifying a custom 'cap_quota' amount to the 'Genode::Connection',
the Gui::Connection now donates enough caps for both the wm and
nitpicker.
Issue #5340
This patch deduces the caps needed for the framebuffer and input RPC
objects from the resources accounted locally within the session. It also
takes precautions for the situation where a client offers too little
resources, prompting the mid-way cancelling of the 'Session_component'
creation. With the patch, the 'ep.manage' operations are rolled back
by the corresponding 'ep.dissolve' operations.
Issue #5340
This patch moves the eager allocation of view capabilities from the
'view' and 'child_view' RPC functions to the 'view_capability' RPC
function, reducing the consumption of capabilities in all scenarios
where views don't need to be shared between GUI sessions.
Issue #5340
The gui_fb client may have installed a custom sync_sigh and mode_sigh.
Reset those signal handlers at the GUI server should the client
disappear. Otherwise, the GUI server (nitpicker) continues to attempt
transmitting sync signals to the no-longer existing component, spamming
the log with "Warning: invalid signal-context capability" messages.
This interface change gives GUI servers the freedom to allocate view
capabilities at the time of request instead of the creation time of the
view. This is useful because view capabilities are rarely needed.
Issue #5242
This patch moves the management of view IDs from the server to the
client side. The former 'create_view' and 'create_child_view'
operations do no longer return a view ID but take a view ID as
argument. While changing those operations, this patch takes the
opportunity to allow for initial view attributes. Combined, those
changes simplify the window manager while accommodating typical
client use cases with less code.
To ease the client-side ID management, the Gui::Connection hosts
a 'view_ids' ID space for optional use. E.g., the new 'Top_level_view'
class uses this ID space for ID allocation. This class accommodates the
most typical use case of opening a single window.
The 'alloc_view_id' RPC function is no longer needed.
Issue #5242
This patch reworks the view-ID handling within the nitpicker GUI server
and the window manager. The namespace of view handles are now represented
as an Id_space. In constrast to the former "handles", which could be
invalid, IDs cannot be semantically overloaded with anything other than
an actual view reference. There is no notion of an invalid handle.
IDs are like C++ references (which cannot be a nullptr).
This change requires the code to be more explicit. E.g., the stacking of
a few at the front-most position can no longer be expressed by passing
an invalid handle as neighbor.
Issue #5242
Express the allocation of a new view handle by a dedicated RPC function
instead of passing an invalid view handle to the existing 'view_handle'
function.
This eliminates the notion of invalid view handles at the GUI session
interface, clearing the way for managing view handles via an Id_space.
Issue #5242
This patch eliminates the use of invalid view handles as special
Session::Command arguments. The TO_FRONT and TO_BACK operations
interpreted as invalid neighbor as top-most or back-most position.
Those corner cases are now expressed via dedicated commands. The
new stacking commands are FRONT, BACK, FRONT_OF, and BEHIND_OF.
While changing the command interface, the patch removes the OP_
prefix from the opcode values.
Issue #5242
- Rename framebuffer_session to framebuffer and
input_session to input as those RPC interfaces are no longer
meant to be used as stand-alone sessions.
- Host Connection::input and Connection::framebuffer as public
members, thereby removing the use of pointers. This simplifies
the client-sized code. E.g., '_gui.input()->pending()' becomes
'_gui.input.pending()'.
Issue #5242
To maintain ease of use at the client side, the OUT_OF_RAM and
OUT_OF_CAPS results are handled at the 'Gui::Connection' now.
Gui::Connection does not inherit the Gui::Session interface any longer,
which allows for the use of different result types.
Issue #5242
Issue #5245
This patch replaces the optional parent argument of the create_view
RPC function by a dedicated create_child_view RPC function. This
is a preparatory step of removing the notion of an invalid handle
as a special case.
Issue #5242
Now, USB audio class devices become available in Sculpt, e.g., for vbox
passthrough, and are not automatically grabbed by the usb_hid class=3
policy. In the future, interface/endpoint level policies will enable
driving the HID interface only from usb_hid while a usb_audio driver
controls the rest of the device.
- Remove exceptions
- Use 'Attr' struct for attach arguments
- Let 'attach' return 'Range' instead of 'Local_addr'
- Renamed 'Region_map::State' to 'Region_map::Fault'
Issue #5245Fixes#5070
The 'Thread_creation_failed' error is now reflected as
'Thread::Start_result' return value. This change also removes the
use of 'Invalid_thread' within core as this exception is an alias
of Cpu_session::Thread_creation_failed.
Issue #5245
For each packet that got stuck with an ARP-cache miss, the router used to send
one ARP request and create one ARP waiter. However, in situations where many
packets target the same IP at one destination domain and during a short period
of time, this causes unnecessary session-quota consumption and network traffic.
This issue becomes especially pressing when taking malicious source peers,
absent destination peers, and packet batching into account.
Therefore, with this commit, the router can accumulate multiple source packets
with the same destination IP at one ARP waiter. This means, that only the first
packet with an ARP-cache for a certain IP sends an ARP request and creates an
ARP waiter. For situations where the ARP request is not answered, this
essentially rate-limits ARP requests for one IP at one destination domain
according to the lifetime of ARP waiters (default: 10s)
Ref #4534
The router used to send an ARP request for a packet before allocating the
corresponding ARP waiter. If the ARP waiter could not be allocated due to
resource exhaustion plus emergency free failed, the packet got dropped and the
router had produced unnecessary network traffic. The commit fixes this by
sending only after successful allocation.
Ref #4534
