From: joelopez333 <[email protected]> REF:https://edk2.groups.io/g/devel/topic/102310377#110456
- Add a read after the final PCI Configuration space write in RootBridgeIoPciAccess. - When configuration space is strongly ordered, this ensures that program execution cannot continue until the completion is received for the previous Cfg-Write, which may have side-effects. Cc: Leif Lindholm <[email protected]> Cc: Ard Biesheuvel <[email protected]> Cc: Sami Mujawar <[email protected]> Cc: Jian J Wang <[email protected]> Cc: Liming Gao <[email protected]> Cc: Hao A Wu <[email protected]> Cc: Ray Ni <[email protected]> Cc: Pedro Falcato <[email protected]> Cc: Michael Brown <[email protected]> Signed-off-by: Joe Lopez <[email protected]> --- MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c index 157a0ada80..4bc774b574 100644 --- a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c +++ b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c @@ -1238,6 +1238,13 @@ RootBridgeIoPciAccess ( } } + // + // Perform readback after write to confirm completion was received for the last write + // + if (!Read) { + PciSegmentRead8 (Address - InStride); + } + return EFI_SUCCESS; } -- 2.25.1 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#110576): https://edk2.groups.io/g/devel/message/110576 Mute This Topic: https://groups.io/mt/102354842/21656 Group Owner: [email protected] Unsubscribe: https://edk2.groups.io/g/devel/unsub [[email protected]] -=-=-=-=-=-=-=-=-=-=-=-
