skiboot 6.0.8 was released on Thursday August 16th, 2018. It replaces skiboot-6.0.7 as the current stable release in the 6.0.x series.

It is recommended that 6.0.8 be used instead of any previous 6.0.x version due to the bug fixes it contains.

The bug fixes are:

  • i2c: Ensure ordering between i2c_request_send() and completion

    i2c_request_send loops waiting for a flag “uc.done” set by the completion routine, and then look for a result code also set by that same completion.

    There is no synchronization, the completion can happen on another processor, so we need to order the stores to uc and the reads from uc so that uc.done is stored last and tested first using memory barriers.

  • i2c: Fix multiple-enqueue of the same request on NACK

    i2c_request_send() will retry the request if the error is a NAK, however it forgets to clear the “ud.done” flag. It will thus loop again and try to re-enqueue the same request causing internal request list corruption.

  • phb4: Disable 32-bit MSI in capi mode

    If a capi device does a DMA write targeting an address lower than 4GB, it does so through a 32-bit operation, per the PCI spec. In capi mode, the first TVE entry is configured in bypass mode, so the address is valid. But with any (bad) luck, the address could be 0xFFFFxxxx, thus looking like a 32-bit MSI.

    We currently enable both 32-bit and 64-bit MSIs, so the PHB will interpret the DMA write as a MSI, which very likely results in an EEH (MSI with a bad payload size).

    We can fix it by disabling 32-bit MSI when switching the PHB to capi mode. Capi devices are 64-bit.

  • capp: Fix the capp recovery timeout comparison

    The current capp recovery timeout control loop in do_capp_recovery_scoms() uses a wrong comparison for return value of tb_compare(). This may cause do_capp_recovery_scoms() to report an timeout earlier than the 168ms stipulated time.

    The patch fixes this by updating the loop timeout control branch in do_capp_recovery_scoms() to use the correct enum tb_cmpval.

  • phb4/capp: Update DMA read engines set in APC_FSM_READ_MASK based on link-width

    Commit 47c09cdfe7a3(“phb4/capp: Calculate STQ/DMA read engines based on link-width for PEC”) update the CAPP init sequence by calculating the needed STQ/DMA-read engines based on link width and populating it in XPEC_NEST_CAPP_CNTL register. This however needs to be synchronized with the value set in CAPP APC FSM Read Machine Mask Register.

    Hence this patch update phb4_init_capp_regs() to calculate the link width of the stack on PEC2 and populate the same values as previously populated in PEC CAPP_CNTL register.

  • core/cpu: Call memset with proper cpu_thread offset