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authorJean Delvare <khali@linux-fr.org>2009-09-22 16:47:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-23 07:39:56 -0700
commit0728bacbba3b0267fa8ca8be69aa43d81b57ab51 (patch)
treea0dd85cb348ad481e92a0d4f45eefdc88fac6e3d /Documentation/volatile-considered-harmful.txt
parent0fcf6ada2b8eb42d132c0846384f1299889609e3 (diff)
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matroxfb: make CONFIG_FB_MATROX_MULTIHEAD=y mandatory
I would like to get rid of option CONFIG_FB_MATROX_MULTIHEAD and just always enable it. There are many reasons for doing this: * CONFIG_FB_MATROX_MULTIHEAD=y is what all x86 distributions do, so it definitely works or we would know by now. * Building the matroxfb driver with CONFIG_FB_MATROX_MULTIHEAD not set results in the following build warning: drivers/video/matrox/matroxfb_crtc2.c: In function 'matroxfb_dh_open': drivers/video/matrox/matroxfb_crtc2.c:265: warning: the address of 'matroxfb_global_mxinfo' will always evaluate as 'true' drivers/video/matrox/matroxfb_crtc2.c: In function 'matroxfb_dh_release': drivers/video/matrox/matroxfb_crtc2.c:285: warning: the address of 'matroxfb_global_mxinfo' will always evaluate as 'true' This is nothing to be worried about, the driver will work fine, but build warnings are still annoying. * The trick to get multihead support without CONFIG_FB_MATROX_MULTIHEAD, which is described in the config help text, no longer works: you can't load the same kernel module more than once. * I fail to see how CONFIG_FB_MATROX_MULTIHEAD=y would make the code significantly slower, contrary to what the help text says. A few extra parameters on the stack here and there can't really slow things down in comaprison to the rest of the code, and register access. * The driver built without CONFIG_FB_MATROX_MULTIHEAD is larger than the driver build with CONFIG_FB_MATROX_MULTIHEAD=y by 8%. * One less configuration option makes things simpler. We add options all the time, being able to remove one for once is nice. It improves testing coverage. And I don't think the Matrox adapters are still popular enough to warrant overdetailed configuration settings. * We should be able to unobfuscate the driver code quite a bit after this change (patches follow.) Signed-off-by: Jean Delvare <khali@linux-fr.org> Acked-by: Petr Vandrovec <vandrove@vc.cvut.cz> Cc: Krzysztof Helt <krzysztof.h1@poczta.fm> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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