On Fri, Sep 07, 2018 at 01:36:14PM +0800, Daniel Drake wrote: <..> > Thomas Martitz reports that this workaround also solves an issue where > the AMD Radeon Polaris 10 GPU on the HP Zbook 14u G5 is unresponsive > after S3 suspend/resume. Where was this claimed? It is not stated in the linked bug: (https://bugs.freedesktop.org/show_bug.cgi?id=105760 > On resume, reprogram the PCI bridge prefetch registers, including the > magic register mentioned above. > > This matches Win10 behaviour, which also rewrites these registers > during S3 resume (checked with qemu tracing). Windows 10 unconditionally rewrites these registers (BAR, I/O Base + Limit, Memory Base + Limit, etc. from top to bottom), see annotations: https://www.spinics.net/lists/linux-pci/msg75856.html Linux has a generic "restore" operation that works backwards from the end of the PCI config space to the beginning, see pci_restore_config_space. Do you have a dmesg where you see the "restoring config space at offset" messages? Would it be reasonable to unconditionally write these registers in pci_restore_config_dword, like Windows does? Kind regards, Peter
