2 Commits (1064e944d03eb7a72c0fa11236d5e69cfd877a71)

Author	SHA1	Message	Date
Antonino A. Daplas	e4fc27618b	[PATCH] fbcon: Console Rotation - Prepare fbcon for console rotation ... This patch series implements generic code to rotate the console at 90, 180, and 270 degrees. The implementation is completely done in the framebuffer console level, thus no changes to the framebuffer layer or to the drivers are needed. Console rotation is required by some Sharp-based devices where the natural orientation of the display is not at 0 degrees. Also, users that have displays that can pivot will benefit by having a console in portrait mode if they so desire. The choice to implement the code in the console layer rather than in the framebuffer layer is due to the following reasons: - it's fast - it does not require driver changes - it can coexist with devices that can rotate the display at the hardware level - it complements graphics applications that can do display rotation The changes to core fbcon are minimal-- recognition of the console rotation angle so it can swap directions, origins and axes (xres vs yres, xpanstep vs ypanstep, xoffset vs yoffset, etc) and storage of the rotation angle per display. The bulk of the code that does the actual drawing to the screen are placed in separate files. Each angle of rotation has separate methods (bmove, clear, putcs, cursor, update_start which is derived from update_var, and clear_margins). To mimimize processing time, the fontdata are pre-rotated at each console switch (only if the font or the angle has changed). The option can be compiled out (CONFIG_FRAMEBUFFER_CONSOLE_ROTATION = n) if rotation is not needed. Choosing the rotation angle can be done in several ways: 1. boot option fbcon=rotate:n, where n = 0 - normal n = 1 - 90 degrees (clockwise) n = 2 - 180 degrees (upside down) n = 3 - 270 degrees (counterclockwise) 2. echo n > /sys/class/graphics/fb[num]/con_rotate where n is the same as described above. It sets the angle of rotation of the current console 3 echo n > /sys/class/graphics/fb[num]/con_rotate_all where n is the same as described above. Globally sets the angle of rotation. GOTCHAS: The option, especially at angles of 90 and 270 degrees, will exercise the least used code of drivers. Namely, at these angles, panning is done in the x-axis, so it can reveal bugs in the driver if xpanstep is set incorrectly. A workaround is to set xpanstep = 0. Secondly, at these angles, the framebuffer memory access can be unaligned if (fontheight * bpp) % 32 ~= 0 which can reveal bugs in the drivers imageblit, fillrect and copyarea functions. (I think cfbfillrect may have this buglet). A workaround is to use a standard 8x16 font. Speed: The scrolling speed difference between 0 and 180 degrees is minimal, somewhere areound 1-2%. At 90 or 270 degress, speed drops down to a vicinity of 30-40%. This is understandable because the blit direction is across the framebuffer "direction." Scrolling will be helped at these angles if xpanstep is not equal to zero, use of 8x16 fonts, and setting xres_virtual >= xres * 2. Note: The code is tested on little-endian only, so I don't know if it will work in big-endian. Please let me know, it will take only less than a minute of your time. This patch prepares fbcon for console rotation and contains the following changes: - add rotate field in struct fbcon_ops to keep fbcon's current rotation angle - add con_rotate field in struct display to store per-display rotation angle - create a private copy of the current var to fbcon. This will prevent fbcon from directly manipulating info->var, especially the fields xoffset, yoffset and vmode. - add ability to swap pertinent axes (xres, yres; xpanstep, ypanstep; etc) depending on the rotation angle - change global update_var() (function that sets the screen start address) as an fbcon method update_start. This is required because the axes, start offset, and/or direction can be reversed depending on the rotation angle. - add fbcon method rotate_font() which will rotate each character bitmap to the correct angle of rotation. - add fbcon boot option 'rotate' to select the angle of rotation at bootime. Currently does nothing until all patches are applied. Signed-off-by: Antonino Daplas <adaplas@pol.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>	20 years ago
Linus Torvalds	1da177e4c3	Linux-2.6.12-rc2 ... Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!	20 years ago