kernel/linux.git/drivers/staging/fbtft, branch v5.15.208

staging: fbtft: core: fix potential memory leak in fbtft_probe_common()

2026-01-19T12:09:32+00:00

[ Upstream commit 47d3949a9b04cbcb0e10abae30c2b53e98706e11 ] fbtft_probe_common() allocates a memory chunk for "info" with fbtft_framebuffer_alloc(). When "display->buswidth == 0" is true, the function returns without releasing the "info", which will lead to a memory leak. Fix it by calling fbtft_framebuffer_release() when "display->buswidth == 0" is true. Fixes: c296d5f9957c ("staging: fbtft: core support") Signed-off-by: Jianglei Nie Signed-off-by: Andy Shevchenko Acked-by: Abdun Nihaal Link: https://patch.msgid.link/20251112192235.2088654-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

staging: fbtft: fix potential memory leak in fbtft_framebuffer_alloc()

2025-08-28T14:24:06+00:00

[ Upstream commit eb2cb7dab60f9be0b435ac4a674255429a36d72c ] In the error paths after fb_info structure is successfully allocated, the memory allocated in fb_deferred_io_init() for info->pagerefs is not freed. Fix that by adding the cleanup function on the error path. Fixes: c296d5f9957c ("staging: fbtft: core support") Signed-off-by: Abdun Nihaal Reviewed-by: Dan Carpenter Link: https://lore.kernel.org/r/20250626172412.18355-1-abdun.nihaal@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

staging: fbtft: core: set smem_len before fb_deferred_io_init call

2024-02-23T07:55:15+00:00

commit 81e878887ff82a7dd42f22951391069a5d520627 upstream. The fbtft_framebuffer_alloc() calls fb_deferred_io_init() before initializing info->fix.smem_len. It is set to zero by the framebuffer_alloc() function. It will trigger a WARN_ON() at the start of fb_deferred_io_init() and the function will not do anything. Fixes: 856082f021a2 ("fbdev: defio: fix the pagelist corruption") Signed-off-by: Peter Suti Link: https://lore.kernel.org/r/20220727073550.1491126-1-peter.suti@streamunlimited.com Signed-off-by: Greg Kroah-Hartman

fbdev: Rename pagelist to pagereflist for deferred I/O

2024-02-23T07:55:13+00:00

[ Upstream commit e80eec1b871a2acb8f5c92db4c237e9ae6dd322b ] Rename various instances of pagelist to pagereflist. The list now stores pageref structures, so the new name is more appropriate. In their write-back helpers, several fbdev drivers refer to the pageref list in struct fb_deferred_io instead of using the one supplied as argument to the function. Convert them over to the supplied one. It's the same instance, so no change of behavior occurs. v4: * fix commit message (Javier) Suggested-by: Sam Ravnborg Signed-off-by: Thomas Zimmermann Reviewed-by: Javier Martinez Canillas Link: https://patchwork.freedesktop.org/patch/msgid/20220429100834.18898-5-tzimmermann@suse.de Stable-dep-of: 33cd6ea9c067 ("fbdev: flush deferred IO before closing") Signed-off-by: Sasha Levin

fbdev: Track deferred-I/O pages in pageref struct

2024-02-23T07:55:13+00:00

[ Upstream commit 56c134f7f1b58be08bdb0ca8372474a4a5165f31 ] Store the per-page state for fbdev's deferred I/O in struct fb_deferred_io_pageref. Maintain a list of pagerefs for the pages that have to be written back to video memory. Update all affected drivers. As with pages before, fbdev acquires a pageref when an mmaped page of the framebuffer is being written to. It holds the pageref in a list of all currently written pagerefs until it flushes the written pages to video memory. Writeback occurs periodically. After writeback fbdev releases all pagerefs and builds up a new dirty list until the next writeback occurs. Using pagerefs has a number of benefits. For pages of the framebuffer, the deferred I/O code used struct page.lru as an entry into the list of dirty pages. The lru field is owned by the page cache, which makes deferred I/O incompatible with some memory pages (e.g., most notably DRM's GEM SHMEM allocator). struct fb_deferred_io_pageref now provides an entry into a list of dirty framebuffer pages, freeing lru for use with the page cache. Drivers also assumed that struct page.index is the page offset into the framebuffer. This is not true for DRM buffers, which are located at various offset within a mapped area. struct fb_deferred_io_pageref explicitly stores an offset into the framebuffer. struct page.index is now only the page offset into the mapped area. These changes will allow DRM to use fbdev deferred I/O without an intermediate shadow buffer. v3: * use pageref->offset for sorting * fix grammar in comment v2: * minor fixes in commit message Signed-off-by: Thomas Zimmermann Reviewed-by: Javier Martinez Canillas Link: https://patchwork.freedesktop.org/patch/msgid/20220429100834.18898-3-tzimmermann@suse.de Stable-dep-of: 33cd6ea9c067 ("fbdev: flush deferred IO before closing") Signed-off-by: Sasha Levin

fbdev: Don't sort deferred-I/O pages by default

2024-02-23T07:55:12+00:00

[ Upstream commit 8c30e2d81bfddc5ab9f6b04db1c0f7d6ca7bdf46 ] Fbdev's deferred I/O sorts all dirty pages by default, which incurs a significant overhead. Make the sorting step optional and update the few drivers that require it. Use a FIFO list by default. Most fbdev drivers with deferred I/O build a bounding rectangle around the dirty pages or simply flush the whole screen. The only two affected DRM drivers, generic fbdev and vmwgfx, both use a bounding rectangle. In those cases, the exact order of the pages doesn't matter. The other drivers look at the page index or handle pages one-by-one. The patch sets the sort_pagelist flag for those, even though some of them would probably work correctly without sorting. Driver maintainers should update their driver accordingly. Sorting pages by memory offset for deferred I/O performs an implicit bubble-sort step on the list of dirty pages. The algorithm goes through the list of dirty pages and inserts each new page according to its index field. Even worse, list traversal always starts at the first entry. As video memory is most likely updated scanline by scanline, the algorithm traverses through the complete list for each updated page. For example, with 1024x768x32bpp each page covers exactly one scanline. Writing a single screen update from top to bottom requires updating 768 pages. With an average list length of 384 entries, a screen update creates (768 * 384 =) 294912 compare operation. Fix this by making the sorting step opt-in and update the few drivers that require it. All other drivers work with unsorted page lists. Pages are appended to the list. Therefore, in the common case of writing the framebuffer top to bottom, pages are still sorted by offset, which may have a positive effect on performance. Playing a video [1] in mplayer's benchmark mode shows the difference (i7-4790, FullHD, simpledrm, kernel with debugging). mplayer -benchmark -nosound -vo fbdev ./big_buck_bunny_720p_stereo.ogg With sorted page lists: BENCHMARKs: VC: 32.960s VO: 73.068s A: 0.000s Sys: 2.413s = 108.441s BENCHMARK%: VC: 30.3947% VO: 67.3802% A: 0.0000% Sys: 2.2251% = 100.0000% With unsorted page lists: BENCHMARKs: VC: 31.005s VO: 42.889s A: 0.000s Sys: 2.256s = 76.150s BENCHMARK%: VC: 40.7156% VO: 56.3219% A: 0.0000% Sys: 2.9625% = 100.0000% VC shows the overhead of video decoding, VO shows the overhead of the video output. Using unsorted page lists reduces the benchmark's run time by ~32s/~25%. v2: * Make sorted pagelists the special case (Sam) * Comment on drivers' use of pagelist (Sam) * Warn about the overhead in comment Signed-off-by: Thomas Zimmermann Acked-by: Sam Ravnborg Acked-by: Andy Shevchenko Link: https://download.blender.org/peach/bigbuckbunny_movies/big_buck_bunny_720p_stereo.ogg # [1] Link: https://patchwork.freedesktop.org/patch/msgid/20220211094640.21632-3-tzimmermann@suse.de Stable-dep-of: 33cd6ea9c067 ("fbdev: flush deferred IO before closing") Signed-off-by: Sasha Levin

staging: fbtft: fb_st7789v: reset display before initialization

2022-03-02T10:48:07+00:00

commit b6821b0d9b56386d2bf14806f90ec401468c799f upstream. In rare cases the display is flipped or mirrored. This was observed more often in a low temperature environment. A clean reset on init_display() should help to get registers in a sane state. Fixes: ef8f317795da (staging: fbtft: use init function instead of init sequence) Cc: stable@vger.kernel.org Signed-off-by: Oliver Graute Link: https://lore.kernel.org/r/20220210085322.15676-1-oliver.graute@kococonnector.com Signed-off-by: Greg Kroah-Hartman

staging: fbtft: Fix error path in fbtft_driver_module_init()

2022-02-16T11:56:22+00:00

[ Upstream commit 426aca16e903b387a0b0001d62207a745c67cfd3 ] If registering the platform driver fails, the function must not return without undoing the spi driver registration first. Fixes: c296d5f9957c ("staging: fbtft: core support") Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20220118181338.207943-1-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

staging/fbtft: Fix backlight

2021-12-01T08:04:41+00:00

commit 7865dd24934ad580d1bcde8f63c39f324211a23b upstream. Commit b4a1ed0cd18b ("fbdev: make FB_BACKLIGHT a tristate") forgot to update fbtft breaking its backlight support when FB_BACKLIGHT is a module. Since FB_TFT selects FB_BACKLIGHT there's no need for this conditional so just remove it and we're good. Fixes: b4a1ed0cd18b ("fbdev: make FB_BACKLIGHT a tristate") Cc: Acked-by: Sam Ravnborg Signed-off-by: Noralf Trønnes Link: https://lore.kernel.org/r/20211105204358.2991-1-noralf@tronnes.org Signed-off-by: Greg Kroah-Hartman

staging/fbtft: Fix braces coding style

2021-08-05T11:05:57+00:00

Add braces to the "for" loop. This way, the kernel coding style is followed. Signed-off-by: Len Baker Link: https://lore.kernel.org/r/20210801085155.3170-4-len.baker@gmx.com Signed-off-by: Greg Kroah-Hartman