From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH] pci: tegra: add MSI dependency Date: Wed, 14 Mar 2018 13:13:14 +0100 Message-ID: <20180314121314.GE8564@ulmo> References: <20180313115218.2246372-1-arnd@arndb.de> <20180314114515.GC8564@ulmo> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="10jrOL3x2xqLmOsH" Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Arnd Bergmann Cc: Lorenzo Pieralisi , Bjorn Helgaas , Manikanta Maddireddy , "open list:TEGRA ARCHITECTURE SUPPORT" , linux-pci , Linux Kernel Mailing List List-Id: linux-tegra@vger.kernel.org --10jrOL3x2xqLmOsH Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Mar 14, 2018 at 01:06:11PM +0100, Arnd Bergmann wrote: > On Wed, Mar 14, 2018 at 12:45 PM, Thierry Reding > wrote: > > On Tue, Mar 13, 2018 at 12:52:05PM +0100, Arnd Bergmann wrote: > >> Building the tegra PCIe host driver without MSI results in a link > >> failure: > >> > >> drivers/pci/host/pci-tegra.o:(.data+0x70): undefined reference to `pci= _msi_unmask_irq' > >> drivers/pci/host/pci-tegra.o:(.data+0x74): undefined reference to `pci= _msi_mask_irq' > >> > >> This adds the same dependency that everyone else uses. > >> > >> Signed-off-by: Arnd Bergmann > >> --- > >> drivers/pci/host/Kconfig | 1 + > >> 1 file changed, 1 insertion(+) > > > > I'm slightly concerned about the dependency. Not that I doubt its > > correctness, but because it could mean that PCI_TEGRA is not visible in > > the default configuration. The only reason why it is currently visible > > is because PCI_MSI is selected by some symbols that also happen to be > > enabled. However, what if at some point those symbols are disabled or > > removed? > > > > Some architectures make sure that PCI_MSI is enabled by selecting it, > > but that's risky, isn't it, because PCI_MSI is user-visible and could > > therefore easily lead to conflicts. > > > > Enabling PCI_MSI in the arm64 defconfig would solve the issue and is > > good enough for me. I've got a couple of changes to that defconfig in > > the Tegra tree for v4.17-rc1, I can add a patch to enable PCI_MSI. > > > > Unless there are any objections. >=20 > I looked at it again and found that this on ARM64, PCI_MSI is always > selected indirectly by ARM_GIC&&PCI, so there is no problem. >=20 > The build failure must have been on 32-bit ARM. Okay, I had assumed that ARM_GIC_V2M (which selects PCI_MSI) was user- visible and hence could be disabled. But it's not, and always enabled on ARM64. On 32-bit we already explicitly enable PCI_MSI via the default configurations. I withdraw my concerns. I see that Lorenzo already applied the patch, so just for the record: Acked-by: Thierry Reding --10jrOL3x2xqLmOsH Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEiOrDCAFJzPfAjcif3SOs138+s6EFAlqpEdoACgkQ3SOs138+ s6F0yA//aupfcFSSBQFcQPwsoeUkqXMoTYfebuIV3TSMq/GUOv1zpfqf0duv9wkE KEJ2avzAX6vcG7AFMi2QsottaskHko0fpNXN0a919lR1uCMxkrjDDtpwrDVyCQHN Mmxy2wHqw2qjKCl0JmTOQf9QVVRiljYDt5vBSpsFpxUzXMzuipjKkfJsV6OrUnzl +/oN1XrsNP0qs/6rShLgObFdkNXBo7MejihrHiLwbzB7z/XGZ2krLrGNquWBY3Ff qt8CKiSSCDEzKtfzAMFP351z/W6KOrlHMhfBuiWCh0D32FqRfhx7mW+7Mpegqcp2 tA6aSNqg+bY705Snk179K6J2uwIcPEiHTETpic0vxbwwliX2+NnrUeF/rkgS6m0o k9IDl7i1Hfi1/aqLNsgffsdpr1x+3K+fWCbcT/WbVR4h5Vaa/1AFC2rdusXmemFT 1ymE1/IKNn2iU6avwINcfGJBHO6lqS5J08/k4U5AKq52rrO8jQvP3302GABcu6cK CLSEItLS8oB77h7RSCtPvyNDD6dFOXIRpGbpzQIF1A/dz0GdKgEYJg1rxj6N9pRg X/q8P8jACEQyWNZVx/wNV6GTDEbdPsPKkohzegAJ3H/rZkrroEdW7IKBokOUf5E7 e5hKV5+w71g0RpFcTYLvKAqUCT9pN6brBTs4XDCgfgMxq20mgiM= =+dWC -----END PGP SIGNATURE----- --10jrOL3x2xqLmOsH--