Date: Fri, 04 Oct 2013 08:56:49 -0700 From: Sean Bruno <sean_bruno@yahoo.com> To: "FreeBSD-scsi@freebsd.org" <FreeBSD-scsi@freebsd.org> Subject: pci_alloc_msi is always called, is this bad? Message-ID: <1380902209.2621.11.camel@localhost> In-Reply-To: <20131003194704.GG41229@kib.kiev.ua> References: <CAFMmRNzWwxe=YVJcC7Lkjqru5eugciwzEQHjgE-Bh-ctOykVNQ@mail.gmail.com> <20131003194704.GG41229@kib.kiev.ua>
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--=-Y0dMsK0bGNdzLsQSS1c9 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I was looking at the recent thread on -stable about mfi(4) and I noted that it appears, if I'm not mistaken, mfi_pci.c::pci_alloc_msi() is *always* invoked regardless of the mfi_msi tuneable. We just ignore the allocated MSI by not setting sc->mfi_irq_rid. Is that harmful? ------------------------------------------------------------------------ 240 /* Allocate IRQ resource. */ 241 sc->mfi_irq_rid =3D 0; 242 count =3D 1; 243 if (mfi_msi && pci_alloc_msi(sc->mfi_dev, &count) =3D=3D 0) { 244 device_printf(sc->mfi_dev, "Using MSI\n"); 245 sc->mfi_irq_rid =3D 1; 246 } ------------------------------------------------------------------------ I would have thought that this would be more correct, avoid calling pci_alloc_msi() if mfi_msi isn't set in the first place. ------------------------------------------------------------------------ sc->mfi_irq_ird =3D 0; count =3D 1; ret =3D 0 if(mfi_msi) ret =3D pci_alloc_msi(sc->mfi_dev, &count); if (!ret) { device_printf(sc->mfi_dev, "Using MSI\n"); sc->mfi_irq_rid =3D 1; } ------------------------------------------------------------------------ Sean --=-Y0dMsK0bGNdzLsQSS1c9 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (FreeBSD) iQEcBAABAgAGBQJSTuVBAAoJEBkJRdwI6BaHbJMH/jrKGb60hQFcmTC/ETEPeSWx fCoxeT+TsICKXycUAXNyc+0ThndqOwUBBDEN+yEMRn1YwbT4jk4WaM2w6yxLXFf3 0Zixb9K3IMNKIrlNZfVgqvEXty56PHRML/kvvlj0GXmEndKRcgQCEaLr/yEc79lK 4XGrk1oJUoZtXljCZr5OEuRM9TYMkxBDRZZuaIxZigqUO0bVOP2gCna4Q7/ixY2p qH5mtYAoq20YSrnSF71MwerO624TVjrusVMUpVkEoZ9+8Fnd2xO/xy1CzhPgZDwE xeTRINRNTXN8NRdAvwHJHova1DcZdzmF5NOyaXGjc1otmZAqHRvAPHfNJbf5XvU= =6UmQ -----END PGP SIGNATURE----- --=-Y0dMsK0bGNdzLsQSS1c9--
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