On Fri, Jun 21, 2019 at 11:33:08AM +0100, David Woodhouse wrote: > On Fri, 2019-06-21 at 10:40 +0200, Gerd Hoffmann wrote: > > Hi, > > > > > Our downstream patch for not initialising NVMe controllers if we aren't > > > going to boot from them, makes its decision based on the priority. > > > > What is the state of that patch btw? > > It's on my "technical debt that I want to kill so we're using a > pristine upstream again" list.
Nice. > > I remember it being posted a while back, suggestion was to make it > > generic (skip init for everything which has a priority higher than > > "HALT", not only nvm), but the discussion went silent quickly and IIRC > > there never was a v2 of that patch ... > > If we do that, then those drives won't be available to INT13h at all. > We'd be saying that just because we don't want to *boot* from them, DOS > can't see them at all. > > Would we assign INT13h drive numbers to them and initialise them on > demand? I don't think that can work because we don't even know if an > ATA drive is present, don't know how many NVMe namespaces are present, > so couldn't assign numbers accordingly. > > Perhaps the first INT13h access to a drive that doesn't exist (0x81 > normally?) would trigger *all* pending drive probes to happen? Can we > even do them that late? > > Or do we make it an option — at build time or through fw_cfg or > something else, to just *not* initialise those drives at all because we > know we're not booting DOS today? It already is configurable. The "HALT" boot priority entry is only added to the list by qemu in case the user specifies "-boot strict=on" on the command line. With strict=on seabios will only boot from devices which have a boot priority explicitly assigned. With strict=off seabios will continue trying the remaining devices in default priority order in case all devices with an assigned priority failed. Extending the strict=on case to also skip the device initialization looks reasonable to me. Faster boot time, less memory consumption, and if you don't want that or need DOS access the second hard disk you can use strict=off (which is the default btw). cheers, Gerd _______________________________________________ SeaBIOS mailing list -- [email protected] To unsubscribe send an email to [email protected]
