From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- Documentation/fb/tridentfb.rst | 78 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 Documentation/fb/tridentfb.rst (limited to 'Documentation/fb/tridentfb.rst') diff --git a/Documentation/fb/tridentfb.rst b/Documentation/fb/tridentfb.rst new file mode 100644 index 000000000..7921c9dee --- /dev/null +++ b/Documentation/fb/tridentfb.rst @@ -0,0 +1,78 @@ +========= +Tridentfb +========= + +Tridentfb is a framebuffer driver for some Trident chip based cards. + +The following list of chips is thought to be supported although not all are +tested: + +those from the TGUI series 9440/96XX and with Cyber in their names +those from the Image series and with Cyber in their names +those with Blade in their names (Blade3D,CyberBlade...) +the newer CyberBladeXP family + +All families are accelerated. Only PCI/AGP based cards are supported, +none of the older Tridents. +The driver supports 8, 16 and 32 bits per pixel depths. +The TGUI family requires a line length to be power of 2 if acceleration +is enabled. This means that range of possible resolutions and bpp is +limited comparing to the range if acceleration is disabled (see list +of parameters below). + +Known bugs: + +1. The driver randomly locks up on 3DImage975 chip with acceleration + enabled. The same happens in X11 (Xorg). +2. The ramdac speeds require some more fine tuning. It is possible to + switch resolution which the chip does not support at some depths for + older chips. + +How to use it? +============== + +When booting you can pass the video parameter:: + + video=tridentfb + +The parameters for tridentfb are concatenated with a ':' as in this example:: + + video=tridentfb:800x600-16@75,noaccel + +The second level parameters that tridentfb understands are: + +======== ===================================================================== +noaccel turns off acceleration (when it doesn't work for your card) + +fp use flat panel related stuff +crt assume monitor is present instead of fp + +center for flat panels and resolutions smaller than native size center the + image, otherwise use +stretch + +memsize integer value in KB, use if your card's memory size is misdetected. + look at the driver output to see what it says when initializing. + +memdiff integer value in KB, should be nonzero if your card reports + more memory than it actually has. For instance mine is 192K less than + detection says in all three BIOS selectable situations 2M, 4M, 8M. + Only use if your video memory is taken from main memory hence of + configurable size. Otherwise use memsize. + If in some modes which barely fit the memory you see garbage + at the bottom this might help by not letting change to that mode + anymore. + +nativex the width in pixels of the flat panel.If you know it (usually 1024 + 800 or 1280) and it is not what the driver seems to detect use it. + +bpp bits per pixel (8,16 or 32) +mode a mode name like 800x600-8@75 as described in + Documentation/fb/modedb.rst +======== ===================================================================== + +Using insane values for the above parameters will probably result in driver +misbehaviour so take care(for instance memsize=12345678 or memdiff=23784 or +nativex=93) + +Contact: jani@astechnix.ro -- cgit v1.3.1