IRC logs for #openrisc Sunday, 2013-03-31

--- Log opened Sun Mar 31 00:00:54 2013
stekernnow I am05:09
andresjkI tried to compile  the module code of a lkmpg> and I get
andresjkI don't know which statements or32-linux cannot compile07:35
andresjkbut I just got a working char driver with this ( code07:36
andresjkanyway, I want to avoid the things that make the or32-linux-gcc break when compiling modules07:38
stekernunregister_chrdev doesn't return anything anymore, so it's not or32-linux-gcc that breaks, it's the example that is old07:41
jeremybennettandresjk: I would guess the compiler is correct (if strict). Use the GCC flag to turn off warnings about void values not being ignored or fix the code.07:41
jeremybennettThis is a common problem with modern GCC. It has become *much* more strict about following the C/C++ standards.07:41
jeremybennettSloppy code that passed in older versions of GCC will trigger warnings and errors now.07:41
stekerni.e. it's now 'void unregister_chrdev'07:42
andresjkif the warnings are ignored does the code will still be stable?07:44
andresjkI don't know where to learn about modules and devices drivers. The books I'm reading were Linux Kernel Module Programming Guide and Linux Device Drivers ver 307:45
andresjkbut they are based on kernel version 2.607:45
jeremybennettandresjk: For the Linux Device Drivers book, I presume you mean This is the definitive work, and is based on Linux
jeremybennettStuff has moved on since 2005, but the core ideas are mostly the sames AFAIK. I'm not really a kernel/driver expert.08:05
jeremybennettThe concepts all remain valid. It's about as up to date as you get in a dead tree. Looking at the O'Reilly website there doesn't seem to be evidence of a 4th edition.08:06
stekernandresjk: if you change the cleanup_module to this it will compile:
andresjkjeremybennett, Yes, I meant that book, Im still reading it as the main guide because the topics are very well cover, but I complement it with examples I find in the internet so I could learn from doing.Still there is plenty tutorials in the internet but most of them are not so recent and spotting those changes its really a pain when learning.08:17
andresjkmy final goal is to do a DMA driver but Im still  learning the basics08:17
andresjkstekern, yes I did that when you spot it out. Thank you. Actually it will never crossed my mind though08:19
andresjkpart of my thesis is to document the sw/hw design flow in OR08:22
andresjkjeremybennett, the -w flag goes after the "make  -C", right?08:24
andresjkbtw, thank you very much guys08:25
jeremybennettandresjk: If you want to change the C flags, I think you'll need something like 'make CLFAGS+="-w..." ...'08:39
jeremybennettMore likely you'll have a configure option to change things.08:39
andresjkjeremybennett, what the order of the GCC parameters? My Makefile doesn't have a flag option.
jeremybennettYou can put them in any order, but if they clash the last one will take precedence. In particular if you use the approach I suggested, your CFLAGS will be overridden by the -w in the makefile (since it is added by += after any existing CFLAGS).09:03
jeremybennettWhat is slightly confusing me is that -w is there anyway, which disables warning messages. Looking at your earlier post, I see it is actually an error, not a warning.09:04
jeremybennettSo you can't disable it. An error means if you ignore it things will break.09:04
jeremybennettI don't have your source code, so I can't see what is happening on line 72 of chardev.c to advise on how to fix it.09:05
jeremybennettAlthough from stekern's earlier comments it sounds like you should be using a different function.09:06
andresjkyes, the new function doesn't return any value thats why the compiler was complaining. The example was old. I never thought of that.09:07
andresjkWell I guess its better to use the right programming techniques and the newest functions to avoid any error/warring and comply the *strict* rules of the modern compilers09:10
andresjkas you said before09:10
andresjkthanks a lot09:15
mor1kx[mor1kx] skristiansson pushed 2 new commits to master:
mor1kxmor1kx/master 2b755b9 Stefan Kristiansson: cappuccino/fetch: avoid ic request when waiting for ibus exception...13:38
mor1kxmor1kx/master 31b298e Stefan Kristiansson: icache, dcache: allow accesses during refill...13:38
stekernI'm actually pretty proud over how that "allow accesses during refill" turned out, *much* better than the old refill ack approach13:42
hjyThis virtual image when it will update?16:31
--- Log closed Mon Apr 01 00:00:55 2013

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