On Mon, Jan 11, 2016 at 01:22:26PM -0800, Danesh Petigara wrote: > The AHCI driver code stops and starts port DMA engines at will > without considering the power state of the particular port. The > AHCI specification isn't very clear on how to handle this scenario, > leaving implementation open to interpretation. > > Broadcom's STB SATA host controller is unable to handle port DMA > controller restarts when the port in question is in low power mode. > When a port enters partial or slumber mode, its PHY is powered down. > When a controller restart is requested, the controller's internal > state machine expects the PHY to be brought back up by software which > never happens in this case, resulting in failures. > > To avoid this situation, logic is added to manually wake up the port > just before its DMA engine is stopped, if the port happens to be in > a low power state. HBA initiated power management ensures that the port > eventually returns to its configured low power state, when the link is > idle (as per the conditions listed in the spec). A new host flag is also > added to ensure this logic is only exercised for hosts with the above > limitation. > > Signed-off-by: Danesh Petigara <dpetigara@xxxxxxxxxxxx> > Reviewed-by: Markus Mayer <mmayer@xxxxxxxxxxxx> Applied to libata/for-4.5-fixes w/ some formatting changes. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
