Messages in this thread | | | Date | Thu, 3 Jun 2004 18:07:28 -0700 | From | Jun Sun <> | Subject | input_event size mismatch between 64bit kernel and 32bit userland ... |
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Pavel Kiryukhin discovered this problem while he is developing 64bit MIPS kernel. With his permission I am forwarding this question to lkml and we would be interested to know how x86_64 solves this problem.
Thanks.
Jun
---------------------------------------------------------------------- Hi all, I stuck in simple situation: USB mouse (or keyboard). n64 kernel (2.4.20), n32 userland.
Userspace application tries to read "input_event" (16 bytes) from "/dev/input/event0" [ read(fd,&key_ev, sizeof(key_ev)) ], input core driver treats "input_event" as 24 bytes structure. It is due to different size of "timeval" (and finally "long") in n64 kernel and n32 userland.
Application gets some garbage as mouse events . No solutions like "ioctl wrappers" applicable in this case.
I don't want to change any arch independent files, but can not find any acceptable solution. It looks like headers "/usr/include/linux/input.h" in root file system and "/include/linux/input.h" in kernel should be the same, (All works fine as soon as I declare a new "input_event" structure in user application that corresponds in size to kernel structure - but this is not acceptable).
Can anybody advice me what to do with the difference in "input_event" structure sizes in o32/n32 userland and n64 kernel? Just a general approach that can be used when driver's read/write operation treat some values as 64 bit while user application tries to read/write 32-bit values (based on the same headers).
Please, don't kick me if solution is simple and obvious.
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