GL9750 SD Host Controller has a 3100us PortTPowerOnTime; however, it enters L1.2 after only ~4us inactivity per PCIe trace. During a suspend/resume process, PCI access operations are frequently longer than 4us apart. Therefore, the device frequently enters and leaves L1.2 during this process, causing longer than desirable suspend/resume time. The total time cost due to this L1.2 exit latency could add up to ~200ms. Considering that PCI access operations are fairly close to each other (though sometimes > 4us), the actual time the device could stay in L1.2 is negligible. Therefore, the little power-saving benefit from ASPM during suspend/resume does not overweight the performance degradation caused by long L1.2 exit latency. Therefore, I am proposing to disable ASPM during a suspend/resume process. Victor Ding (2): PCI/ASPM: Disable ASPM until its LTR and L1ss state is restored mmc: sdhci-pci-gli: Disable ASPM during a suspension drivers/mmc/host/sdhci-pci-core.c | 2 +- drivers/mmc/host/sdhci-pci-gli.c | 46 +++++++++++++++++++++++++++++-- drivers/mmc/host/sdhci-pci.h | 1 + drivers/pci/pci.c | 11 ++++++++ drivers/pci/pci.h | 2 ++ drivers/pci/pcie/aspm.c | 2 +- 6 files changed, 60 insertions(+), 4 deletions(-) -- 2.30.0.284.gd98b1dd5eaa7-goog
