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charset="us-ascii" Content-Transfer-Encoding: quoted-printable DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1585021826; bh=iU3l0hKHebzvA0hQ77JENKXmGpG0NLH34MUrCP9l0Ho=; h=X-PGP-Universal:ARC-Seal:ARC-Message-Signature: ARC-Authentication-Results:From:To:CC:Subject:Thread-Topic: Thread-Index:Date:Message-ID:References:In-Reply-To: Accept-Language:X-MS-Has-Attach:X-MS-TNEF-Correlator:msip_labels: authentication-results:x-originating-ip:x-ms-publictraffictype: x-ms-office365-filtering-correlation-id:x-ms-traffictypediagnostic: x-microsoft-antispam-prvs:x-ms-oob-tlc-oobclassifiers: x-forefront-prvs:x-forefront-antispam-report:received-spf: x-ms-exchange-senderadcheck:x-microsoft-antispam: x-microsoft-antispam-message-info: x-ms-exchange-antispam-messagedata:x-ms-exchange-transport-forked: MIME-Version:X-MS-Exchange-CrossTenant-Network-Message-Id: X-MS-Exchange-CrossTenant-originalarrivaltime: X-MS-Exchange-CrossTenant-fromentityheader: X-MS-Exchange-CrossTenant-id:X-MS-Exchange-CrossTenant-mailboxtype: X-MS-Exchange-CrossTenant-userprincipalname: X-MS-Exchange-Transport-CrossTenantHeadersStamped:X-OriginatorOrg: Content-Language:Content-Type:Content-Transfer-Encoding; b=CUap3Hf5MggmkR4DPPf3Gqk/9K4s02NyaVcDhDWR7NEL1Xi4+khPhPSZi6DwMh2Uy ZfhjwjoW0FELOug+CL9cUmWzggTCGwl2GNsq3187MsqwHnftANJSZ0DSlCPIq5q5uA XU1tmAoGv/AzBBYd6U1HBFwEbOBiFB4Vu0gKDgTH2V1Etq+RSsoJO8STZYiR6epZ5H nELanEXlULkIVUdo5nzo8UtivwvuKIXl5aaH00CwM3P/soJ4UE3prOSzmZIHtvmg9a nGu4fDV6iYYRzZp1rH88Bl9X6Ecnmf9zC/Kq7B+5cItDcWAuLfBXVxWRowCyijNjBm grU0nz9bb8Cpg== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Kai-Heng > -----Original Message----- > From: linux-i2c-owner@vger.kernel.org > On Behalf Of Kai-Heng Feng > Sent: Monday, March 23, 2020 10:21 AM > To: Ajay Gupta > Cc: Wolfram Sang ; Andy Shevchenko > ; open list:I2C CONTROLLER DRIVER > FOR NVIDIA GPU ; open list kernel@vger.kernel.org> > Subject: Re: [PATCH] i2c: nvidia-gpu: Handle timeout correctly in > gpu_i2c_check_status() >=20 > External email: Use caution opening links or attachments >=20 >=20 > Hi Ajay, >=20 > > On Mar 24, 2020, at 00:47, Ajay Gupta wrote: > > > > Kai-Heng > > > >> -----Original Message----- > >> From: Kai-Heng Feng > >> Sent: Sunday, March 22, 2020 10:38 PM > >> To: Ajay Gupta > >> Cc: Wolfram Sang ; Andy Shevchenko > >> ; open list:I2C CONTROLLER DRIVER > >> FOR NVIDIA GPU ; open list >> kernel@vger.kernel.org> > >> Subject: Re: [PATCH] i2c: nvidia-gpu: Handle timeout correctly in > >> gpu_i2c_check_status() > >> > >> External email: Use caution opening links or attachments > >> > >> > >>> On Mar 12, 2020, at 00:58, Kai-Heng Feng > >>> > >> wrote: > >>> > >>> Nvidia card may come with a "phantom" UCSI device, and its driver > >>> gets stuck in probe routine, prevents any system PM operations like > suspend. > >>> > >>> Let's handle the unaccounted case that the target time equals to > >>> jiffies in gpu_i2c_check_status(), so the UCSI driver can let the > >>> probe fail as it should. > > If status is not seen in 999.5 ms then I don't see any reason why it > > will come exactly at 1000ms. In fact, we expect status to be seen > > within 160ms as per I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT (16 > cycle) and > > I2C_MST_I2C0_TIMING_SCL_PERIOD_100KHZ (10ms/cycle) programmed in > > I2C_MST_I2C0_TIMING Register. We already have enough extra time to > > look For response. >=20 > This is to handle when there's no response. >=20 > When the while loop terminates because of "time_is_after_jiffies(target)" > (i.e. target <=3D jiffies), we also need to to handle "target =3D=3D jiff= ies" case in the > following if clause to properly timeout. Ok got it. The change looks fine to me. Acked-by: Ajay Gupta Thanks > nvpublic >=20 > I don't think I2C timings here can affect jiffies. >=20 > Kai-Heng >=20 > > > > Thanks > >> nvpublic > >>> > >>> Fixes: c71bcdcb42a7 ("i2c: add i2c bus driver for NVIDIA GPU") > >>> Signed-off-by: Kai-Heng Feng > >> > >> A gentle ping... > >> > >>> --- > >>> drivers/i2c/busses/i2c-nvidia-gpu.c | 2 +- > >>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>> > >>> diff --git a/drivers/i2c/busses/i2c-nvidia-gpu.c > >>> b/drivers/i2c/busses/i2c-nvidia-gpu.c > >>> index 62e18b4db0ed..1988e93c7925 100644 > >>> --- a/drivers/i2c/busses/i2c-nvidia-gpu.c > >>> +++ b/drivers/i2c/busses/i2c-nvidia-gpu.c > >>> @@ -88,7 +88,7 @@ static int gpu_i2c_check_status(struct gpu_i2c_dev > >> *i2cd) > >>> usleep_range(500, 600); > >>> } while (time_is_after_jiffies(target)); > >>> > >>> - if (time_is_before_jiffies(target)) { > >>> + if (time_is_before_eq_jiffies(target)) { > >>> dev_err(i2cd->dev, "i2c timeout error %x\n", val); > >>> return -ETIMEDOUT; > >>> } > >>> -- > >>> 2.17.1 > >>> > >