drm/mipi-dbi: display a cropped region of an oversized framebuffer - #7589
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HorseyofCoursey wants to merge 3 commits into
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drm/mipi-dbi: display a cropped region of an oversized framebuffer#7589HorseyofCoursey wants to merge 3 commits into
HorseyofCoursey wants to merge 3 commits into
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mipi_dbi_fb_dirty() takes the damage rectangle from drm_atomic_helper_damage_merged(), which is expressed in framebuffer coordinates and already clipped to the plane's source rectangle. It then passed that rectangle straight to mipi_dbi_set_window_address(), which is correct only while the source rectangle starts at (0,0) - i.e. while the framebuffer is exactly panel-sized. If a driver allows a framebuffer larger than the panel and the plane selects a sub-region with a non-zero src_x/src_y, the controller was still addressed in framebuffer coordinates, so the wrong part of the panel was written and an out-of-range window could be programmed. Pass the integer plane source origin down to mipi_dbi_fb_dirty() and subtract it when programming the column/page address. The copy into the transfer buffer still uses the framebuffer-coordinate rectangle, so it keeps reading the correct pixels from an oversized source. With a panel-sized framebuffer src_x/src_y are zero and behaviour is unchanged. Signed-off-by: Jonathan Frazin <frazinjonathan@gmail.com>
The driver set mode_config.max_width/max_height equal to the panel
dimensions, so KMS rejected any framebuffer that was not exactly
panel-sized:
ili9341 spi0.0: bad framebuffer width 480, should be >= 240 && <= 240
Raise the maximums so userspace can allocate a larger framebuffer and
choose the displayed region through the plane's source rectangle - a
crop / pan with no scaling. The minimums, the fixed display mode and
the connector are unchanged, and drm_mipi_dbi now translates the source
offset when addressing the controller.
The transfer buffer is sized from the display mode, and the plane check
(drm_mipi_dbi_plane_helper_atomic_check) forbids scaling and
repositioning, so the flushed rectangle stays bounded by the panel size
regardless of the framebuffer dimensions.
Signed-off-by: Jonathan Frazin <frazinjonathan@gmail.com>
Same change as the preceding ili9341 patch: mode_config.max_width/height were pinned to the panel dimensions, rejecting any framebuffer that was not exactly panel-sized. Raise them so a sub-region of a larger framebuffer can be displayed via the plane source rectangle, now that drm_mipi_dbi translates the source offset. The fixed mode, the minimums and the connector are unchanged; the plane check forbids scaling and repositioning and tx_buf is sized from the mode, so the flushed rectangle stays bounded by the panel. Compile-tested only; the functional testing was done on ili9341. Signed-off-by: Jonathan Frazin <frazinjonathan@gmail.com>
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Currently a drm/tiny MIPI-DBI panel can only scan out a framebuffer that
is exactly panel-sized, always from the origin. This series lets a client
allocate a larger framebuffer and choose the displayed region via the
plane source rectangle — a crop / pan with no scaling.
Pass the integer plane src origin into mipi_dbi_fb_dirty() and
subtract it in mipi_dbi_set_window_address(). The buffer copy still
uses framebuffer coordinates so it reads the right pixels from an
oversized source. src=(0,0) behaviour is unchanged.
2/3. drm/tiny/{ili9341,hx8357d}: raise mode_config.max_width/height,
which were pinned to the panel size and rejected any non-panel-sized
framebuffer. Fixed mode / minimums / connector unchanged; the plane
check forbids scaling and repositioning and tx_buf is mode-sized, so
the flushed rectangle stays bounded by the panel.
Change 1 is in the shared core; changes 2/3 are the per-driver limit
bump (the max_* values moved into the tiny drivers in 7.2). Entirely
within the DBI path — no shared shadow-plane / damage-helper changes.
Tested (Pi Zero 2 W, generic 2.4" 240x320 ILI9341, landscape):
width"), displayed from origin.
kmstest -f 480x640-RG16 -v <x>,<y>-320x240:the displayed region tracks the source rectangle.
performance regression.
hx8357d: compile-tested only.
Follow-up, not in this series: mipi_dbi_fb_dirty() can skip the tx_buf
repack when the framebuffer stride matches the panel width (rows are
contiguous). Independent of this feature; will send separately.
Thanks to @6by9 for the guidance throughout! (: