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[103.229.16.4]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2b06e61cacbsm44735525ad.72.2026.03.18.22.42.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 18 Mar 2026 22:42:13 -0700 (PDT) Message-ID: <05c818c9-8be7-4680-9902-1ae56f374fc7@oss.qualcomm.com> Date: Thu, 19 Mar 2026 13:42:10 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 04/12] scsi: ufs: core: Add support for TX Equalization To: =?UTF-8?B?UGV0ZXIgV2FuZyAo546L5L+h5Y+LKQ==?= , "beanhuo@micron.com" , "mani@kernel.org" , "avri.altman@wdc.com" , "bvanassche@acm.org" , "martin.petersen@oracle.com" Cc: "linux-scsi@vger.kernel.org" , "adrian.hunter@intel.com" , "alim.akhtar@samsung.com" , "James.Bottomley@HansenPartnership.com" , "quic_nguyenb@quicinc.com" , "linux-kernel@vger.kernel.org" References: <20260308151409.3779137-1-can.guo@oss.qualcomm.com> <20260308151409.3779137-5-can.guo@oss.qualcomm.com> <42587e16218f1c51dbcbe6bb1639a843e10bcd80.camel@mediatek.com> <1318f77eca87a01815214e7fb0178281871c9b1f.camel@mediatek.com> Content-Language: en-US From: Can Guo In-Reply-To: <1318f77eca87a01815214e7fb0178281871c9b1f.camel@mediatek.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Proofpoint-ORIG-GUID: 5wu1OkNQvGcYMjUbXNe7sB5BxVNpwHnS X-Proofpoint-GUID: 5wu1OkNQvGcYMjUbXNe7sB5BxVNpwHnS X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzE5MDA0MiBTYWx0ZWRfX70JiHQbbGWvM y4VfgI4+Ns7IHvAMadz6+f6oCtrZM/OhHufo4zmUPaW1XX/6ZMtxzB2az7J+jbuLwzohpLzcs4k Iks9EJSDzCcQGRy0ulMsdwVZvyHqjTOA9rM5Xx8JIEvEcQQmTOjD2upK9fflZq67eoI0B5y37tv OTRH/AdGrJCzOa8n3/3cCgC0GYW9IOALFmePI+ORxk4Metyg4y0x7LCgYX2pqCqMBLoe5L1NyS/ AQuySQ4rAaKEnwNXZ/R+edKQ9/lAw6q8ENxbmoPxQZTu+wAnylfw6ySqiJMbNeg7Aw6VG9GLU0a CkmdjHqfWgtD7p3ui/I+Nwjlvk1XyzoD9yKosBd713nC6vlOEXeGnoUyXJVNsWqTItr9EBCWTSk aNOXgnyuUe5zCtYsjXETtv63jxWfroxH8kAqnK16pWE9lCF+6tXWXbNfLm0PctTIZI9b0ZMqx49 0iEIKpjTG5tI3h6mt5Q== X-Authority-Analysis: v=2.4 cv=WO9yn3sR c=1 sm=1 tr=0 ts=69bb8cb7 cx=c_pps a=cmESyDAEBpBGqyK7t0alAg==:117 a=nuhDOHQX5FNHPW3J6Bj6AA==:17 a=IkcTkHD0fZMA:10 a=Yq5XynenixoA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=ZpdpYltYx_vBUK5n70dp:22 a=8fswfkG2DZOyL5G1xN4A:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=1OuFwYUASf3TG4hYMiVC:22 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-03-19_01,2026-03-17_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 suspectscore=0 lowpriorityscore=0 impostorscore=0 adultscore=0 clxscore=1015 spamscore=0 malwarescore=0 phishscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2603050001 definitions=main-2603190042 Hi Peter, On 3/17/2026 9:08 PM, Peter Wang (王信友) wrote: > > On Tue, 2026-03-17 at 15:22 +0800, Can Guo wrote: > > Here is the consideration: > > > > 1. Scanning all 64 PreShoot/DeEmphasis combinations cost (much) more > > time > >    a. This could impact bootup KPI > >    b. During TX EQTR, IOs are paused, when one conducts a re- > > training, > > the IOs could > >         be paused for too long. > > > > Hi Can, > > Yes, it will take some time, but according to the specification, > we need to find the best FOM, so the default value should still > follow the specification. It is just a default value of module parameter , one can change it via boot cmdline. But since you have asked it twice, I will change the default value to true in next version. > > > > 2. As per our study in the past few months, the optimal/best > > combination > > is most > >      likely within the 8 presets, which is true for both Host TX > > lanes > > and Device TX lanes. > > > > Host may be true, but there are so many devices, and new UFS 5.0 > devices will keep being released in the future. How can we > guarantee that the optimal/best combination is most likely > within the 8 presets? > > > > 3. Even if sometime the optimal settings which fall out of the 8 > > presets, they are very > >      close to optimal one found within the 8 presets. > > > > Could you share what led you to this conclusion? > From the scores reported by each vendor, it’s hard for us to > determine what a difference of a few points actually means. > > > > So, scanning the 8 presets only is more cost-efficient. > > > > > > > +ufshcd_tx_eqtr_result_examine(struct ufshcd_tx_eq_params > > > > *old_params, > > > > +                             struct ufshcd_tx_eq_params > > > > *new_params) > > > > +{ > > > > +       int lane; > > > > + > > > > +       if (!old_params->is_valid) > > > > +               return; > > > > > > Is is_valid always false, causing a return here? > > It can be valid if we are here (again) because one conducts a re- > > training. > > > > > Then, should this function be moved to [07/12], which supports > retraining? Sure, I will move in next version. Thanks, Can Guo. > > Thanks. > Peter > > > > ************* MEDIATEK Confidentiality Notice ******************** > The information contained in this e-mail message (including any > attachments) may be confidential, proprietary, privileged, or otherwise > exempt from disclosure under applicable laws. It is intended to be > conveyed only to the designated recipient(s). Any use, dissemination, > distribution, printing, retaining or copying of this e-mail (including its > attachments) by unintended recipient(s) is strictly prohibited and may > be unlawful. If you are not an intended recipient of this e-mail, or believe > that you have received this e-mail in error, please notify the sender > immediately (by replying to this e-mail), delete any and all copies of > this e-mail (including any attachments) from your system, and do not > disclose the content of this e-mail to any other person. Thank you!