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[84.124.213.91]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a94c118e19sm10345e9.5.2026.10.27.11.15.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Oct 2026 11:15:03 -0700 (PDT) Message-ID: <6ae0ea27.08a8f783.2e4276.0395@mx.google.com> Date: Tue, 27 Oct 2026 11:15:03 -0700 (PDT) From: D. Manresa To: dave.stevenson@raspberrypi.com, linux-media@vger.kernel.org Cc: antoine.pichot@gmail.com, sakari.ailus@linux.intel.com, mchehab@kernel.org, dan.scally@ideasonboard.com, hansg@kernel.org, andriy.shevchenko@linux.intel.com, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 1/7] media: i2c: ov7251: Fix link frequency index In-Reply-To: References: <20261026111032.88355-1-antoine.pichot@gmail.com> <20261026111032.88355-2-antoine.pichot@gmail.com> <6ae07c65.e52dcaf0.293af3.e7d5@mx.google.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Hi Dave, On Tue, 27 Oct 2026 at 16:50, Dave Stevenson wrote: > @D. Manresa it'd be worth trying using a prediv instead of (post)div: > .pre_div = 0x04, > .mult = 0x85, > .div = 0x01, Our mails crossed, and that is exactly the change I had just finished measuring, from a test patch Antoine sent me. It fixes the link on this receiver: thirteen 150-frame runs at 30 fps, every one 150 of 150 in 5.2 s with zero dropped buffers and zero CSI-2 error lines, against seven bad runs out of ten with the index fix alone, three of them hard stalls. i2c readback mid-stream confirms 0x30b4 = 0x04 and 0x30b1 = 0x01 with link_frequency still 319200000, so the link rate is unchanged and only the VCO moved. Full numbers are in my other mail on this thread, which went out a few minutes after yours arrived and does not mention you only because I had not yet seen it. So the 19.2 MHz / 319.2 MHz mode you could not test behaves exactly as your 24 MHz oscilloscope measurements predict. Dan's instinct in the parallel branch was right too: it was the driver's PLL settings and not the value ipu-bridge advertises. One data point on VBLANK, since you raised it. With 2/7 of this series the 90 fps mode runs at vblank 92, and in its clean runs it logged no CSI-2 errors and no corruption I could see here. I did not go below 40, so I can neither confirm nor contradict that part. D. Manresa (Written with AI assistance, directed and reviewed by me.)