On Thu, Apr 01, 2010 at 01:47:40, Jon Povey wrote: > Andrew Morton wrote: > > On Wed, 31 Mar 2010 20:43:29 -0500 "Ambrose, Martin" <[email protected]> > > wrote: > > >>> If the calling process has signal_pending() (say, someone hit ^C) > >>> then wait_event_interruptible_timeout() will fall straight through > >>> with -ERESTARTSYS. Will this cause the driver to malfunction at > >>> all? > >> > >> I don't think so since the driver doesn't make use of this > >> information in any way. This is just status to the caller that the > >> current frame has finished DMA'ing out of the framebuffer. > >> > >> Could you maybe propose a scenario/use case where you think it is > >> problematic? I could then either reason why it should be OK or > >> I'll create a test harness and see how the driver can/should be > >> modified. > > > > Gee, I dunno - I don't understand the driver to that level. If you're > > OK with this wait being interrupted by a signal and the driver handles > > it OK then fine, that's a feature. > > > > To test it I suppose you should give your test app a signal handler > > and blast kills at it from another process. > > Jumping in.. > > This should not cause a problem for the driver; its purpose is to tell > userland that it can > write to the buffer without corrupting graphics (as presumably it is > double-buffering and > the other buffer is now being DMA'd from by the hardware). > > At worst, if the userland software doesn't handle this correctly it may draw > one bad frame of graphics. Although if it's had a ctrl-C it probably has > bigger things to worry about. > > If the app wants to handle signals it needs to consider such things.. I would > not expect the driver to do anything other than what this patch does.
Thanks Jon. I agree. If no further objections I'll leave this as is. Regards, Martin _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
