[Core] Faster matrix comparison #25971
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zvecr
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Jan 25, 2026
quantum/matrix.h
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| void matrix_init(void); | ||
| /* scan all key states on matrix */ | ||
| uint8_t matrix_scan(void); | ||
| bool matrix_scan(void); |
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This changes the API that custom matrix has to implement, breaking anything that already exists.
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| bool matrix_changed = false; | ||
| for (uint8_t row = 0; row < MATRIX_ROWS && !matrix_changed; row++) { | ||
| matrix_changed |= matrix_previous[row] ^ matrix_get_row(row); | ||
| } |
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This was intentional, as the result of matrix_scan for custom matrix is not consistently implemented.
quantum/matrix_common.c
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| changed = debounce(raw_matrix, matrix + thisHand, ROWS_PER_HAND, changed) | matrix_post_scan(); | ||
| #else | ||
| changed = debounce(raw_matrix, matrix, changed); | ||
| changed = debounce(raw_matrix, matrix, ROWS_PER_HAND, changed); |
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Why is a 4th argument being introduced again?
| } | ||
| } | ||
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| matrix_row_t matrix_previous[MATRIX_ROWS]; |
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Moving this increases what "full" custom matrix would have to implement, cascading changes to multiple keyboards.
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Description
matrix_previous[MATRIX_ROWS]into the respectivematrix.candmatrix_common.c.matrix_scan()matrix_scan()now returns changed, rather than a comparisonmemcmpover looping per rowMy speed up went from 13800 scans to 14800 scans ~6% increase (with custom matrix) 👍
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