Intel Introduces New "BFF" Linux Driver To Deal With Aging Silicon & Stuck Bits
([Intel] 3 Hours Ago
Intel BFF)
- Reference: 0001654406
- News link: https://www.phoronix.com/news/Intel-BFF-Driver-Stuck-Bits
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Intel is preparing to introduce a new Linux driver named "BFF" for dealing with aging processor silicon where bits may become stuck over time.
Back for Sapphire Rapids, Intel [1]introduced the In-Field Scan "IFS" for silicon failure testing prior to commissioning new servers or more pronounced for testing of aging hardware. As the latest for dealing with aging processor silicon and as new hardware designs and manufacturing nodes become even more complex, ahead of next year's Diamond Rapids launch they are preparing a new driver for supporting new functionality. The Intel "BFF" driver sent out yesterday in initial patch form is for dealing with aging silicon where bits may become stuck.
Longtime Intel Linux engineer Tony Luck explained of the BFF driver used for resetting "bitfix" filters:
"Some Intel CPUs implement a "bitfix filter" to suppress reporting of the same corrected errors repeatedly in the case where aging silicon develops stuck bits.
But when systems run for weeks, or months, the filters may become clogged with transient errors.
When the filter is full (indicated by a "yellow" signature in a machine check bank) clear the filter. This may make space for additional hard errors.
Save a time stamp when clearing a filter. Log with "WARN" severity if the filter overflows quickly (in ten minutes or less)."
The Intel BFF driver is initially wired up for Xeon 7 Diamond Rapids processors with the bitfix filter support. The Bitfix Filter "BFF" hardware support isn't found with any existing Intel processor models as further confirmed in the LKML discussion over this new driver.
The Intel BFF driver is out for review on the [2]Linux kernel mailing list . It's too late for ushering into Linux v7.3's merge window but presumably could be ready for v7.4. With Diamond Rapids not launching until later in 2027, there's still time to get it into the mainline kernel.
[1] https://www.phoronix.com/news/Intel-In-Field-Scan
[2] https://lore.kernel.org/platform-driver-x86/20260825181526.13203-1-tony.luck@intel.com/
Back for Sapphire Rapids, Intel [1]introduced the In-Field Scan "IFS" for silicon failure testing prior to commissioning new servers or more pronounced for testing of aging hardware. As the latest for dealing with aging processor silicon and as new hardware designs and manufacturing nodes become even more complex, ahead of next year's Diamond Rapids launch they are preparing a new driver for supporting new functionality. The Intel "BFF" driver sent out yesterday in initial patch form is for dealing with aging silicon where bits may become stuck.
Longtime Intel Linux engineer Tony Luck explained of the BFF driver used for resetting "bitfix" filters:
"Some Intel CPUs implement a "bitfix filter" to suppress reporting of the same corrected errors repeatedly in the case where aging silicon develops stuck bits.
But when systems run for weeks, or months, the filters may become clogged with transient errors.
When the filter is full (indicated by a "yellow" signature in a machine check bank) clear the filter. This may make space for additional hard errors.
Save a time stamp when clearing a filter. Log with "WARN" severity if the filter overflows quickly (in ten minutes or less)."
The Intel BFF driver is initially wired up for Xeon 7 Diamond Rapids processors with the bitfix filter support. The Bitfix Filter "BFF" hardware support isn't found with any existing Intel processor models as further confirmed in the LKML discussion over this new driver.
The Intel BFF driver is out for review on the [2]Linux kernel mailing list . It's too late for ushering into Linux v7.3's merge window but presumably could be ready for v7.4. With Diamond Rapids not launching until later in 2027, there's still time to get it into the mainline kernel.
[1] https://www.phoronix.com/news/Intel-In-Field-Scan
[2] https://lore.kernel.org/platform-driver-x86/20260825181526.13203-1-tony.luck@intel.com/