Messages in this thread | | | Date | Wed, 29 Sep 2004 14:35:48 +0100 | From | Keith Whitwell <> | Subject | Re: New DRM driver model - gets rid of DRM() macros! |
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Christoph Hellwig wrote: > On Wed, Sep 29, 2004 at 02:29:24PM +0100, Keith Whitwell wrote: > >>Christoph Hellwig wrote: >> >> >>> - drm_flush is a noop. a NULL ->flush does the same thing, just easier >>> - dito or ->poll >>> - dito for ->read >> >>Pretty sure you couldn't get away with null for these in 2.4, at least. > > > Umm, of course you could. There's only a hanfull instance defining a > ->flush at all. Similarly all file_ops for regular files and many char > devices don't have ->poll. no ->read is pretty rare but 2.4 chæcks it > aswell.
I tried it, led to crashes (panics, I guess) & the change had to be reverted. On reverting the crashes stopped. This was for poll and read:
revision 1.12 date: 2003-04-23 23:42:28 +0000; author: keithw; state: Exp; lines: +13 -0 Install dummy/noop read & poll fops unless the driver has replacements. ---------------------------- revision 1.11 date: 2003-04-22 08:06:13 +0000; author: keithw; state: Exp; lines: +0 -94 remove DRM read, poll and write_string
I didn't do any more investigation & the behaviour may well be different nowadays.
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