goodix55x4: add host-side finger detection via frame diff polling - #4
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sidevesh wants to merge 1 commit into
Open
goodix55x4: add host-side finger detection via frame diff polling#4sidevesh wants to merge 1 commit into
sidevesh wants to merge 1 commit into
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The MCU's FDT-down reply on this firmware doesn't actually block until a real touch — it returns immediately regardless of the configured threshold. This causes the driver to capture frames before any finger is present. Fix by polling captured frames against the calibration background image (empty_img) using a per-pixel absolute difference score. A real touch raises the score well above the background noise floor (~4-5) to ~750+; the threshold is set conservatively at 100. Polls up to 100 times with 100ms delay between attempts before giving up with a retry error.
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The MCU's FDT-down reply on this firmware doesn't actually block until a real touch — it returns immediately regardless of the configured threshold. This causes the driver to capture frames before any finger is present.
Fix by polling captured frames against the calibration background image (empty_img) using a per-pixel absolute difference score. A real touch raises the score well above the background noise floor (~4-5) to ~750+; the threshold is set conservatively at 100. Polls up to 100 times with 100ms delay between attempts before giving up with a retry error.
@TheWeirdDev this has resolved the issue of the fingerprint getting captured immediately without waiting for me to even touch the sensor and then failing on its own after trying multiple times continuously,
wonder what your thoughts are on this and if this issue is affecting this model sensor on all laptops and if this fix is applicable to all or not,
fyi: thanks for working on this project