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PCI/ASPM: Make Intel DG2 L1 acceptable latency unlimited

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Intel DG2 discrete graphics PCIe endpoints advertise L1 acceptable exit
latency to be < 1us even though they can actually tolerate unlimited exit
latencies just fine. Quirk the L1 acceptable exit latency for these
endpoints to be unlimited so ASPM L1 can be enabled.

[bhelgaas: use FIELD_GET/FIELD_PREP, wordsmith comment & commit log]
Link: https://lore.kernel.org/r/20220405093810.76613-1-mika.westerberg@linux.intel.com
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
This commit is contained in:
Mika Westerberg 2022-04-05 12:38:10 +03:00 committed by Bjorn Helgaas
parent 3123109284
commit 03038d84ac
1 changed files with 47 additions and 0 deletions
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47
drivers/pci/quirks.c
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@ -12,6 +12,7 @@
* file, where their drivers can use them.
*/
#include <linux/bitfield.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/export.h>
@ -5895,3 +5896,49 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1533, rom_bar_overlap_defect);
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1536, rom_bar_overlap_defect);
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1537, rom_bar_overlap_defect);
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1538, rom_bar_overlap_defect);
#ifdef CONFIG_PCIEASPM
/*
* Several Intel DG2 graphics devices advertise that they can only tolerate
* 1us latency when transitioning from L1 to L0, which may prevent ASPM L1
* from being enabled. But in fact these devices can tolerate unlimited
* latency. Override their Device Capabilities value to allow ASPM L1 to
* be enabled.
*/
static void aspm_l1_acceptable_latency(struct pci_dev *dev)
{
u32 l1_lat = FIELD_GET(PCI_EXP_DEVCAP_L1, dev->devcap);
if (l1_lat < 7) {
dev->devcap |= FIELD_PREP(PCI_EXP_DEVCAP_L1, 7);
pci_info(dev, "ASPM: overriding L1 acceptable latency from %#x to 0x7\n",
l1_lat);
}
}
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x4f80, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x4f81, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x4f82, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x4f83, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x4f84, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x4f85, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x4f86, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x4f87, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x4f88, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x5690, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x5691, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x5692, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x5693, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x5694, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x5695, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56a0, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56a1, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56a2, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56a3, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56a4, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56a5, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56a6, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56b0, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56b1, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56c0, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56c1, aspm_l1_acceptable_latency);
#endif