From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andreas Kemnade Subject: Re: [PATCH RESEND] phy: phy-twl4030-usb: fix denied runtime access Date: Tue, 18 Sep 2018 18:16:19 +0200 Message-ID: <20180918181619.2e266f0d@aktux> References: <20180917052254.12336-1-andreas@kemnade.info> <20180917175131.GA104770@dtor-ws> <20180917205634.6a320cad@aktux> <20180917222345.GA203020@dtor-ws> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; boundary="Sig_/hF17.lQIoc7SEI58RHUA+gC"; protocol="application/pgp-signature" Return-path: In-Reply-To: <20180917222345.GA203020@dtor-ws> Sender: linux-kernel-owner@vger.kernel.org To: Dmitry Torokhov Cc: kishon@ti.com, lee.jones@linaro.org, daniel.thompson@linaro.org, wsa@the-dreams.de, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org, Discussions about the Letux Kernel List-Id: linux-omap@vger.kernel.org --Sig_/hF17.lQIoc7SEI58RHUA+gC Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Hi, On Mon, 17 Sep 2018 15:23:45 -0700 Dmitry Torokhov wrote: > On Mon, Sep 17, 2018 at 08:56:34PM +0200, Andreas Kemnade wrote: > > Hi Dmitry, > >=20 > > On Mon, 17 Sep 2018 10:51:31 -0700 > > Dmitry Torokhov wrote: > > =20 > > > Hi Andreas, > > >=20 > > > On Mon, Sep 17, 2018 at 07:22:54AM +0200, Andreas Kemnade wrote: =20 > > > > When runtime is not enabled, pm_runtime_get_sync() returns -EACCESS, > > > > the counter will be incremented but the resume callback not called, > > > > so enumeration and charging will not start properly. > > > > To avoid that happen, wait and try again later. > > > >=20 > > > > Practically this happens when the device is woken up from suspend by > > > > plugging in usb. > > > >=20 > > > > Signed-off-by: Andreas Kemnade > > > > --- > > > > drivers/phy/ti/phy-twl4030-usb.c | 9 +++++++++ > > > > 1 file changed, 9 insertions(+) > > > >=20 > > > > diff --git a/drivers/phy/ti/phy-twl4030-usb.c b/drivers/phy/ti/phy-= twl4030-usb.c > > > > index a44680d64f9b..1f3cf4e48383 100644 > > > > --- a/drivers/phy/ti/phy-twl4030-usb.c > > > > +++ b/drivers/phy/ti/phy-twl4030-usb.c > > > > @@ -552,6 +552,15 @@ static irqreturn_t twl4030_usb_irq(int irq, vo= id *_twl) > > > > =20 > > > > status =3D twl4030_usb_linkstat(twl); > > > > =20 > > > > + /* we might get here too early when runtime is not ready yet > > > > + * and we will get an EACCESS later, so try again later > > > > + */ =20 > > >=20 > > > How exactly can this happen? What disables (and later re-enables) > > > runtime PM? =20 > > If the whole resume process is started by plugging in usb, the > > interrupt will be triggered still in the resume process so that=20 > > runtime resume is not yet possible, pm_runtime_get_sync() returns > > EACCESS =20 >=20 > I see. This all seems a bit wonky, to be honest. I would expect that the > driver would have a suspend routine that disables interrupt and also > configure interrupt for wakeup (enable_irq_wake) and kick bus scanning > from there instead of aborting interrupt handler... >=20 well, that seems doable. So there will be a v2. > > =20 > > > How can we guarantee that the interrupt will be > > > re-triggered? > > > =20 > > The interrupt will not be re-triggered but the handler will be > > called at some other places... > > =20 > > > > + if (!pm_runtime_enabled(twl->dev)) { > > > > + cancel_delayed_work(&twl->id_workaround_work); > > > > + schedule_delayed_work(&twl->id_workaround_work, HZ); > > > > + return IRQ_HANDLED; > > > > + } > > > > + =20 > > ... for example by this delayed work which is already there. =20 >=20 > If we decide to keep this, it should be mod_delayed_work() I think. >=20 Well, is that valid for the other uses of id_workaround_work() (which are clearly required)? So there should be a second, independent cleanup patch for the existing uses? Regards, Andreas=20 --Sig_/hF17.lQIoc7SEI58RHUA+gC Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEE7sDbhY5mwNpwYgrAfb1qx03ikyQFAluhJNMACgkQfb1qx03i kyRqSRAAxyTwGaRnx00uUC5GgMf7USmj0z/RC/wWCX+8F/UnZfMyvGl4zgEeE9wd uXMgKTAJxHCIYSgp106rgo3Y/IbqMZ1t0o27HuD7fmmL2HJ8MuxiZkNYVzkfuKz4 518CgFqBi8q6SP+zAG9TI3bQZJapFbxORoSdRAQGcfFDYeicCx5ObUJh4BRMI5Ey sX9g237+QzuNMTYvTYa0Vh0HiceHnkAlD2Sj2+jgMFHS7cKitj4bnAajxCNG5y/i C0OZ4JUsm4d3Ztea7HEi4g5TI97l24sHraYhHbcPZ8twVlccgEwGWrtsuDHclXFc DFbaeqWRsvLhw0jtdRRtKGiB40cX5W8WAVFTG3HEzBbostSzeln7hGb3vPR1a5rO 4MdWLFTDTFUZyxEfm1CD7qRap7zD/v+choz1ya8kAe/f4plTBdLKWxkC+pZzQRij nsy+kmC3PSsTH/w6CpBWv883ZiESLijxeLvmP8/69vZTaqhUzRz01tVIvSHtoUgm lEDSDkMvLpktKUuchUV3tpeyjPU74iuZsCJC+yEIQnYg2TPdOAUKLhpEeGC7NiYr P7F5xANEntc13a4fotAK6k2pA4Z6ftvseWCvfgavWoUfgIRShk/mfqI8wbctS5Fo DRaM5Zk/Fp5Nsqy7FsjA0P4pUj/0C+bHkavbqQjl6SxF388tTKk= =miFt -----END PGP SIGNATURE----- --Sig_/hF17.lQIoc7SEI58RHUA+gC--