There is no hardware block to perform a transpose (required for rot 90 or 270) whilst composing the output to HDMI or other live output.
The transposer block is only available when writing the composed scene back to memory.
The old firmware drivers cheated and kicked the transposer at the frame rate with the framebuffer exposed by the kernel used as the source for that. That kernel framebuffer was never rendered direct to the display.
"video=....rotate=270" largely only tells fbcon (the code to render the text to the console) that it should rotate the output. It does NOT rotate the framebuffer whilst being rendered unless the hardware can support such a function.
You can use "video=....panel_orientation=[normal|upside_down|left_side_up|right_side_up]" to set the panel_orientation property on the connector. As that is a property that DRM advertises, more clients should pay attention to it.
The transposer block is only available when writing the composed scene back to memory.
The old firmware drivers cheated and kicked the transposer at the frame rate with the framebuffer exposed by the kernel used as the source for that. That kernel framebuffer was never rendered direct to the display.
"video=....rotate=270" largely only tells fbcon (the code to render the text to the console) that it should rotate the output. It does NOT rotate the framebuffer whilst being rendered unless the hardware can support such a function.
You can use "video=....panel_orientation=[normal|upside_down|left_side_up|right_side_up]" to set the panel_orientation property on the connector. As that is a property that DRM advertises, more clients should pay attention to it.
Statistics: Posted by 6by9 — Fri Jan 03, 2025 2:36 pm
