On Mon, 31 Dec 2018, Finn Thain wrote:
On Sun, 30 Dec 2018, James Bottomley wrote:
That said, as has been pointed out, the current #ifdef has a failing
corner case when both are modular (because the code should then be
included). The runtime macro that correctly expresses this is
IS_REACHABLE(CONFIG_NVRAM).
No, in the case of CONFIG_NVRAM=m, the conditional code is deliberately
excluded. This is discussed in the patch description. The convention on
PPC32 is that device drivers drop support for NVRAM in this situation.
I've adopted the PPC32 convention here because M68K drivers and PPC32
drivers have to co-exist (I'm thinking of valkyriefb, but there are other
examples).
I agree with your comment in principle, that these drivers should be using
IS_REACHABLE(CONFIG_NVRAM), not defined(CONFIG_NVRAM).
$ grep -lrw CONFIG_NVRAM drivers/
drivers/video/fbdev/matrox/matroxfb_base.c
drivers/video/fbdev/platinumfb.c
drivers/video/fbdev/controlfb.c
drivers/video/fbdev/valkyriefb.c
drivers/video/fbdev/imsttfb.c
drivers/scsi/atari_scsi.c
$
But I think this is not the fault of this patch; it's just a historical
accident.
Having said that, I will rework this series to convert all of the above
drivers to IS_REACHABLE(CONFIG_NVRAM). I think it would be an improvement.
Besides, it seems likely that some rework involving ppc_md will be needed
too because as Arnd pointed out, it would be good to avoid two sets of
nvram accessor methods.
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