From dd05add7b2b6004c5fa3a1f276f56d8668f86b65 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Sat, 26 Sep 2026 19:20:30 -0300 Subject: netfs: zero the tail of a short DIO/unbuffered read The buffered read collector zero-fills the tail of a short read that stops below the inode's i_size (netfs_clear_unread()), so a read that races an extending write still returns the expected number of bytes. The non-buffered collector path does no such thing: it just records how much was transferred. Add the same zero-fill for the non-buffered case, gated on NETFS_SREQ_CLEAR_TAIL: a subreq's source sets that flag when a short result from it is known to be safe to treat as a hole, as opposed to NETFS_SREQ_HIT_EOF, which means the read genuinely ran off the end of the file and should be reported short as-is. Only CLEAR_TAIL should zero-fill here; a real EOF must stay a real short read. No source currently sets CLEAR_TAIL on an unbuffered/DIO subrequest, so this is inert on its own -- a following change teaches cifs to set it in the one case that needs it. Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item") Reviewed-by: David Howells Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Christian Brauner Cc: Matthew Wilcox Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org --- Documentation/gpu/vc4.rst | 108 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 108 insertions(+) create mode 100644 Documentation/gpu/vc4.rst (limited to 'Documentation/gpu/vc4.rst') diff --git a/Documentation/gpu/vc4.rst b/Documentation/gpu/vc4.rst new file mode 100644 index 000000000..5e5e92e40 --- /dev/null +++ b/Documentation/gpu/vc4.rst @@ -0,0 +1,108 @@ +===================================== + drm/vc4 Broadcom VC4 Graphics Driver +===================================== + +.. kernel-doc:: drivers/gpu/drm/vc4/vc4_drv.c + :doc: Broadcom VC4 Graphics Driver + +Display Hardware Handling +========================= + +This section covers everything related to the display hardware including +the mode setting infrastructure, plane, sprite and cursor handling and +display, output probing and related topics. + +Pixel Valve (DRM CRTC) +---------------------- + +.. kernel-doc:: drivers/gpu/drm/vc4/vc4_crtc.c + :doc: VC4 CRTC module + +HVS +--- + +.. kernel-doc:: drivers/gpu/drm/vc4/vc4_hvs.c + :doc: VC4 HVS module. + +HVS planes +---------- + +.. kernel-doc:: drivers/gpu/drm/vc4/vc4_plane.c + :doc: VC4 plane module + +HDMI encoder +------------ + +.. kernel-doc:: drivers/gpu/drm/vc4/vc4_hdmi.c + :doc: VC4 Falcon HDMI module + +DSI encoder +----------- + +.. kernel-doc:: drivers/gpu/drm/vc4/vc4_dsi.c + :doc: VC4 DSI0/DSI1 module + +DPI encoder +----------- + +.. kernel-doc:: drivers/gpu/drm/vc4/vc4_dpi.c + :doc: VC4 DPI module + +VEC (Composite TV out) encoder +------------------------------ + +.. kernel-doc:: drivers/gpu/drm/vc4/vc4_vec.c + :doc: VC4 SDTV module + +KUnit Tests +=========== + +The VC4 Driver uses KUnit to perform driver-specific unit and +integration tests. + +These tests are using a mock driver and can be ran using the +command below, on either arm or arm64 architectures, + +.. code-block:: bash + + $ ./tools/testing/kunit/kunit.py run \ + --kunitconfig=drivers/gpu/drm/vc4/tests/.kunitconfig \ + --cross_compile aarch64-linux-gnu- --arch arm64 + +Parts of the driver that are currently covered by tests are: + * The HVS to PixelValve dynamic FIFO assignment, for the BCM2835-7 + and BCM2711. + +Memory Management and 3D Command Submission +=========================================== + +This section covers the GEM implementation in the vc4 driver. + +GPU buffer object (BO) management +--------------------------------- + +.. kernel-doc:: drivers/gpu/drm/vc4/vc4_bo.c + :doc: VC4 GEM BO management support + +V3D binner command list (BCL) validation +---------------------------------------- + +.. kernel-doc:: drivers/gpu/drm/vc4/vc4_validate.c + :doc: Command list validator for VC4. + +V3D render command list (RCL) generation +---------------------------------------- + +.. kernel-doc:: drivers/gpu/drm/vc4/vc4_render_cl.c + :doc: Render command list generation + +Shader validator for VC4 +--------------------------- +.. kernel-doc:: drivers/gpu/drm/vc4/vc4_validate_shaders.c + :doc: Shader validator for VC4. + +V3D Interrupts +-------------- + +.. kernel-doc:: drivers/gpu/drm/vc4/vc4_irq.c + :doc: Interrupt management for the V3D engine -- cgit v1.3.1