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Mon, 06 Jul 2026 04:41:11 -0700 (PDT) X-Received: by 2002:a05:622a:208:b0:50e:6311:7380 with SMTP id d75a77b69052e-51c4be99299mr82578061cf.6.1783338069294; Mon, 06 Jul 2026 04:41:09 -0700 (PDT) Received: from [192.168.120.193] ([178.235.128.140]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-69a19cf68f5sm4059006a12.13.2026.07.06.04.41.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 06 Jul 2026 04:41:08 -0700 (PDT) Message-ID: <4f865aaf-a400-4dc6-acaa-80dc22a36af7@oss.qualcomm.com> Date: Mon, 6 Jul 2026 13:41:05 +0200 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 v2] i2c: qcom-geni: Add dynamic transfer timeout based on transfer length and frequency To: Aniket Randive , mukesh.savaliya@oss.qualcomm.com, viken.dadhaniya@oss.qualcomm.com, andi.shyti@kernel.org, sumit.semwal@linaro.org, christian.koenig@amd.com Cc: linux-i2c@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, naresh.maramaina@oss.qualcomm.com References: <20260705135739.4038826-1-aniket.randive@oss.qualcomm.com> Content-Language: en-US From: Konrad Dybcio In-Reply-To: <20260705135739.4038826-1-aniket.randive@oss.qualcomm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Proofpoint-GUID: 8Dlh4jqOzRcppnLB1wqA1vfLmKM8cIIR X-Proofpoint-ORIG-GUID: 8Dlh4jqOzRcppnLB1wqA1vfLmKM8cIIR X-Authority-Analysis: v=2.4 cv=CPYamxrD c=1 sm=1 tr=0 ts=6a4b9458 cx=c_pps a=mPf7EqFMSY9/WdsSgAYMbA==:117 a=PRfkaYvzSr8QmIIGAkY2Sg==:17 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=Um2Pa8k9VHT-vaBCBUpS:22 a=QdFQMySKPoxOC9Zsaq0A:9 a=QEXdDO2ut3YA:10 a=dawVfQjAaf238kedN5IG:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzA2MDExOCBTYWx0ZWRfX/Upfe6KP7tZU vJozCGP/b6bF3RjXx9DBuQGUeYnjELUHzQrEbnSnYqmfidxlmv762tAgwjv/+kQW5IyN0Un71a9 xJHNWMx8XN4/FE37jOI5uTB8x67FmLqrsplDsqwmhEcz7hbVQjXutw2Ta1ZCz974ZwW5NfS6SeP OSQ9jr+ZUDMPgcCfnbsxjup13rfLPFYr6vwX4yLIebbC+8AKL/+/zys8FAI3s/RdqjdExRrqrpa D/ig8k3F6sr7S8dzrY+rBBgoWy7DY33SPCqTDhss8wW6OVJo7sp78AAzUFmGA7MVxJIWaQRJxBc YRLu/eBnXEED5GEkT74AxSkAS7wKZTW2PcqPnOur7hPm4WRTajKvpp9bdOFQuftkLsEqPiVSHlH BSUkWnRIYhI5Ry0u1yVjM0MTlmjL37EaSo9G6lardnS2/Hz35QgWQd+6k9b1KhNpyxWKTYJ03hs zegdrVdcuo7VEKHc16g== X-Proofpoint-Spam-Info: AW1haW4tMjYwNzA2MDExOCBTYWx0ZWRfX2L5xAsJFNqEI NrZbIWy4oooWd2+U3aSFeH71bgJAdQSHM3/4zR11FmqQj6mbfB1Yy6vQbQjI7ue4Uo3A1zkdVX8 gitUcWqRcaogmE1kqXo9vhHZ5n61Edo= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-06_01,2026-07-06_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 adultscore=0 clxscore=1015 priorityscore=1501 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 lowpriorityscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607060118 On 7/5/26 3:57 PM, Aniket Randive wrote: > The driver uses a static XFER_TIMEOUT of HZ (1 second) for all transfers > regardless of message length or bus frequency, causing unnecessary > delays on error paths. > > Compute the timeout dynamically from message length and bus frequency > with a 10x safety margin over the theoretical wire time and a 300ms > floor. For GPI multi-descriptor transfers, use the maximum message > length across all queued messages as the per-completion timeout. What's the reason for a 0.3 s floor? Why a 10x safety margin specifically? [...] > +static unsigned long geni_i2c_xfer_timeout(struct geni_i2c_dev *gi2c, size_t len) > +{ > + size_t bit_cnt = len * 9; > + size_t bit_usec = (bit_cnt * USEC_PER_SEC) / gi2c->clk_freq_out; mult_frac() Konrad