From: "Prasad Malisetty (Temp)" <pmaliset@qti.qualcomm.com>
To: Stephen Boyd <swboyd@chromium.org>,
"Prasad Malisetty (Temp) (QUIC)" <quic_pmaliset@quicinc.com>,
"agross@kernel.org" <agross@kernel.org>,
"bhelgaas@google.com" <bhelgaas@google.com>,
"bjorn.andersson@linaro.org" <bjorn.andersson@linaro.org>,
"kw@linux.com" <kw@linux.com>,
"linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>,
"rajatja@google.com" <rajatja@google.com>,
"refactormyself@gmail.com" <refactormyself@gmail.com>,
"robh@kernel.org" <robh@kernel.org>
Cc: "Veerabhadrarao Badiganti (QUIC)" <quic_vbadigan@quicinc.com>,
"Rama Krishna (QUIC)" <quic_ramkri@quicinc.com>,
"manivannan.sadhasivam@linaro.org"
<manivannan.sadhasivam@linaro.org>
Subject: RE: [PATCH v2] [RFC PATCH] PCI: Update LTR threshold based on LTRME bit
Date: Tue, 5 Apr 2022 06:24:39 +0000 [thread overview]
Message-ID: <CO1PR02MB853729533D004EB671B273BAE9E49@CO1PR02MB8537.namprd02.prod.outlook.com> (raw)
In-Reply-To: <CAE-0n51HZKXCtrzf3_5wnoCZfhRoq8AqmUwsdk31iaiteVRDYg@mail.gmail.com>
Hi Stephen,
Thanks for the review and comments. Please find my comments inline below.
Thanks
-Prasad
> -----Original Message-----
> From: Stephen Boyd <swboyd@chromium.org>
> Sent: Friday, March 18, 2022 12:37 AM
> To: Prasad Malisetty (Temp) (QUIC) <quic_pmaliset@quicinc.com>;
> agross@kernel.org; bhelgaas@google.com; bjorn.andersson@linaro.org;
> kw@linux.com; linux-arm-msm@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-pci@vger.kernel.org; lorenzo.pieralisi@arm.com; rajatja@google.com;
> refactormyself@gmail.com; robh@kernel.org
> Cc: Veerabhadrarao Badiganti (QUIC) <quic_vbadigan@quicinc.com>; Rama
> Krishna (QUIC) <quic_ramkri@quicinc.com>;
> manivannan.sadhasivam@linaro.org
> Subject: Re: [PATCH v2] [RFC PATCH] PCI: Update LTR threshold based on
> LTRME bit
>
> WARNING: This email originated from outside of Qualcomm. Please be wary of
> any links or attachments, and do not enable macros.
>
> Quoting Prasad Malisetty (2022-03-07 10:59:09)
> > Update LTR threshold scale and value based on LTRME (Latency
> > Tolenrance Reporting Mechanism) from device capabilities.
> >
> > In ASPM driver, LTR threshold scale and value is updating based on
> > tcommon_mode and t_poweron values. In kioxia NVMe,
> > L1.2 is failing due to LTR threshold scale and value is greater values
> > than max snoop/non snoop value.
> >
> > In general, updated LTR threshold scale and value should be less than
> > max snoop/non snoop value to enter the device into L1.2 state.
> >
> > Signed-off-by: Prasad Malisetty <quic_pmaliset@quicinc.com>
> >
>
> Any Fixes tag?
No, we don’t have any fixes tag as this is new issue identified in kioxia NVMe only as of now.
>
> > ---
> > Changes since v1:
> > - Added missing variable declaration in v1 patch.
> > ---
> > drivers/pci/pcie/aspm.c | 12 +++++++++---
> > 1 file changed, 9 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index
> > a96b742..a67746c 100644
> > --- a/drivers/pci/pcie/aspm.c
> > +++ b/drivers/pci/pcie/aspm.c
> > @@ -463,6 +463,7 @@ static void aspm_calc_l1ss_info(struct pcie_link_state
> *link,
> > u32 val1, val2, scale1, scale2;
> > u32 t_common_mode, t_power_on, l1_2_threshold, scale, value;
> > u32 ctl1 = 0, ctl2 = 0;
> > + u32 cap;
> > u32 pctl1, pctl2, cctl1, cctl2;
> > u32 pl1_2_enables, cl1_2_enables;
> >
> > @@ -499,9 +500,14 @@ static void aspm_calc_l1ss_info(struct
> pcie_link_state *link,
> > * Table 5-11. T(POWER_OFF) is at most 2us and T(L1.2) is at
> > * least 4us.
>
> Can this comment be updated to include why LTR cap matters?
Sure, I will update the comment in next patch version.
>
> > */
> > - l1_2_threshold = 2 + 4 + t_common_mode + t_power_on;
> > - encode_l12_threshold(l1_2_threshold, &scale, &value);
> > - ctl1 |= t_common_mode << 8 | scale << 29 | value << 16;
> > + pcie_capability_read_dword(child, PCI_EXP_DEVCAP2, &cap);
> > + if (!(cap & PCI_EXP_DEVCAP2_LTR)) {
> > + l1_2_threshold = 2 + 4 + t_common_mode + t_power_on;
> > + encode_l12_threshold(l1_2_threshold, &scale, &value);
> > + ctl1 |= scale << 29 | value << 16;
> > + }
> > +
> > + ctl1 |= t_common_mode;
next prev parent reply other threads:[~2022-04-05 6:24 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-07 18:59 [PATCH v2] [RFC PATCH] PCI: Update LTR threshold based on LTRME bit Prasad Malisetty
2022-03-17 19:07 ` Stephen Boyd
2022-04-05 6:24 ` Prasad Malisetty (Temp) [this message]
2022-04-05 18:57 ` Stephen Boyd
2022-04-05 16:08 ` Bjorn Helgaas
2022-04-12 22:46 ` Bjorn Helgaas
2022-06-01 12:23 ` [PATCH v3] PCI/ASPM: Update LTR threshold based upon reported max latencies Krishna chaitanya chundru
2022-06-01 12:27 ` Krishna Chaitanya Chundru
2022-06-02 8:29 ` Manivannan Sadhasivam
2022-06-02 9:59 ` Krishna Chaitanya Chundru
2022-06-03 7:54 ` [PATCH v4] " Krishna chaitanya chundru
2022-06-08 22:22 ` Stephen Boyd
2022-06-10 5:08 ` [PATCH v5] " Krishna chaitanya chundru
2022-06-15 13:23 ` Krishna Chaitanya Chundru
2022-07-15 8:28 ` Manivannan Sadhasivam
2022-07-15 11:28 ` Krishna Chaitanya Chundru
2022-06-15 17:39 ` Manivannan Sadhasivam
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