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Mon, 2 Dec 2019 13:27:39 +0000 Received: from AM5PR1001MB0994.EURPRD10.PROD.OUTLOOK.COM ([fe80::5525:87da:ca4:e8df]) by AM5PR1001MB0994.EURPRD10.PROD.OUTLOOK.COM ([fe80::5525:87da:ca4:e8df%7]) with mapi id 15.20.2495.014; Mon, 2 Dec 2019 13:27:39 +0000 From: Adam Thomson To: Marco Felsch , Adam Thomson CC: Support Opensource , "wim@linux-watchdog.org" , "linux@roeck-us.net" , "linux-watchdog@vger.kernel.org" , "kernel@pengutronix.de" Subject: RE: [PATCH] watchdog: da9062: add power management ops Thread-Topic: [PATCH] watchdog: da9062: add power management ops Thread-Index: AQHVphAFwdyccq+61U6+GK1Hr/H0vaemod1wgAAQYwCAAAQN0IAAH0kAgAADedA= Date: Mon, 2 Dec 2019 13:27:39 +0000 Message-ID: References: <20191128171931.22563-1-m.felsch@pengutronix.de> <20191202105646.xzqzlu2jnel4qbuv@pengutronix.de> <20191202130314.dzne7eh2b5sb46c2@pengutronix.de> In-Reply-To: <20191202130314.dzne7eh2b5sb46c2@pengutronix.de> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-originating-ip: [165.225.80.228] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 2bccb099-c179-41b1-450b-08d7772b6766 x-ms-traffictypediagnostic: AM5PR1001MB1042: x-ms-exchange-sharedmailbox-routingagent-processed: True x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:9508; 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charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: diasemi.com X-MS-Exchange-CrossTenant-Network-Message-Id: 2bccb099-c179-41b1-450b-08d7772b6766 X-MS-Exchange-CrossTenant-originalarrivaltime: 02 Dec 2019 13:27:39.7069 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 511e3c0e-ee96-486e-a2ec-e272ffa37b7c X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: PVkR/TlVkUnegdg08OzxbGY+1+wTN9b96PTes51C9PEA8SP+8Hf56GoZbkJJWqTpDgome/2FHPeipL5XNclNmkkcmruYzgwAd2jV4OUw5LA= X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM5PR1001MB1042 Sender: linux-watchdog-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org Hi Marco, > > Hmmm. Wouldn't that then be a board specific fix rather than this chang= e? > > Am concerned relying on software to reenable the watchdog on resume cou= ld > allow > > for a hang scenario potentially if that code never gets to execute. Oth= er > > systems shouldn't need this fix, assuming they don't have issues at the= HW > > level, so this this seems like it could be making those systems less ro= bust. If > > we are to do this at the driver level, maybe this should be an option t= hrough DT > > to help faulty systems, but I'm thinking this shouldn't be default beha= viour. >=20 > I don't think that we should rely on the OTP values. Those values are > set by Dialog, the SoM manufacturers or by the customer itself and the > time shows that this is error prone too. At least if the customer or the > SoM manufacturer don't ask the Dialog Support.. >=20 > You're right with the (re-)enabling but there are other drivers using > such an approach.. IMHO it is safer to go this way rather than trust > the OTP and the PCB layout. I would rather add a dt-compatible to tell > the driver to do nothing during suspend/resume e.g.: >=20 > - dlg,use-hw-pm >=20 > or something. Because the user needs to validate the PCB and the OTP > values. The thing is the DT FW is supposed to be fairly static so I would rather no= t enforce this change on users if they adopt a kernel version with this updat= e in. I also still think it's safer if the HW does this for us. I would have hope= d for most designs this would be caught in early bring up where it can be rectifi= ed with minimal impact, although I'm guessing that's not the case in your scen= ario. > Regards, > Marco