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    matroxfb: make CONFIG_FB_MATROX_MULTIHEAD=y mandatory · 0728bacb
    Jean Delvare 提交于
    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: NJean Delvare <khali@linux-fr.org>
    Acked-by: NPetr Vandrovec <vandrove@vc.cvut.cz>
    Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
    Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    0728bacb
matroxfb_base.h 18.2 KB