From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [RFC/PATCH 0/7] Powerpc MSI Implementation From: Michael Ellerman To: Segher Boessenkool In-Reply-To: References: <1162884080.585336.70559261997.qpush@cradle> <1162885276.28571.444.camel@localhost.localdomain> <20061107080257.GA5874@kroah.com> <1162963101.20271.18.camel@localhost.localdomain> <1163028836.7630.16.camel@localhost.localdomain> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-HvawTaMEbIZmxcC+gEuX" Date: Mon, 13 Nov 2006 17:05:31 +1100 Message-Id: <1163397931.7410.86.camel@localhost.localdomain> Mime-Version: 1.0 Cc: Greg KH , linuxppc-dev@ozlabs.org, "Eric W. Biederman" , linux-pci@atrey.karlin.mff.cuni.cz, "David S. Miller" Reply-To: michael@ellerman.id.au List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --=-HvawTaMEbIZmxcC+gEuX Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Thu, 2006-11-09 at 08:36 +0100, Segher Boessenkool wrote: > > Looking closer most of them are 5 bits, the high 5 bits, and happen to > > sit next to reserved fields (which must be zero), so reading the byte > > should work in practice. But for a few of them you'll get cruft in the > > low bits. > > > > I don't know what they were thinking when they decided to have 3 and 5 > > bit capability fields, and then specify some of them as being a byte > > wide as well. Perhaps the spec committee had a big night out ;) > > > > I was going to write a generic version of pci_find_ht_capability() (as > > suggested by Segher), so along with that I'll clean up the #defines to > > just be the 3 or 5 bit capability codes, and then have a shift for > > getting the capability out of the byte. > > > > Users will still need to know if they're looking for a 3 or 5 bit > > capability, but we can encapsulate that in pci_find_ht_capability() =20 > > and > > hopefully most people won't have to see the difference. >=20 > Keep the defines the full 8 bits and put all the knowledge > about which bits are relevant into pci_find_ht_capability()? > If you do shifting you can get clashes (say, 0b00110 vs. 0b110), > and this would make for simpler code, too. That's what I did .. I think? :) cheers --=20 Michael Ellerman OzLabs, IBM Australia Development Lab wwweb: http://michael.ellerman.id.au phone: +61 2 6212 1183 (tie line 70 21183) We do not inherit the earth from our ancestors, we borrow it from our children. - S.M.A.R.T Person --=-HvawTaMEbIZmxcC+gEuX Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.3 (GNU/Linux) iD8DBQBFWAsrdSjSd0sB4dIRAufEAKCS8Wl0MTZaUpnZrVDUDhSEBZJsWwCcCeEN 3pxkvAAwFbSPJcXpbwGW5gk= =ABWq -----END PGP SIGNATURE----- --=-HvawTaMEbIZmxcC+gEuX--