On Thu, Feb 24, 2022 at 12:06:09AM +0800, Jisheng Zhang wrote: > On Wed, Feb 23, 2022 at 11:46:22AM +0000, Lorenzo Pieralisi wrote: > > On Sun, Jan 23, 2022 at 08:02:42PM +0800, Jisheng Zhang wrote: > > > On Sun, Dec 26, 2021 at 03:40:19PM +0800, Jisheng Zhang wrote: > > > > If the host which makes use of the IP's integrated MSI Receiver losts > > > > power during suspend, we call dw_pcie_setup_rc() to reinit the RC. But > > > > dw_pcie_setup_rc() always set the pp->irq_mask[ctrl] as ~0, so the mask > > > > register is always set as 0xffffffff incorrectly, thus the MSI can't > > > > work after resume. > > > > > > > > Fix this issue by moving pp->irq_mask[ctrl] initialization to > > > > dw_pcie_host_init(), so we can correctly set the mask reg during both > > > > boot and resume. > > > > > > > > Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxx> > > > > > > Hi all, > > > > > > This patch can still be applied to the latest linus tree. Do you want > > > me to rebase and send out a new version? > > > > > > Without this patch, dwc host MSI interrupt(if use the IP's integrated > > > MSI receiver) can't work after resume. Could it be picked up as a fix > > > for v5.17? > > > > The tricky bit with this patch is that it is not clear what piece of > > logic is lost on power down and what not. IIUC MSI interrupt controller > > logic is kept so it does not need to be saved/restored (but in > > You may mean the external MSI interrupt controller case, but here the > focus is the integrated MSI Receiver in the IP. Normally, after > suspending to ram, the dwc IP would lost power, so the integrated MSI > Receiver also lost power. > > > dw_pcie_setup_rc() we overwrite PCIE_MSI_INTR0_ENABLE even if it > > is not needed on resume - actually, it can even be destructive). > > > > For the integrated MSI Receiver case, since the entire IP power is lost, > so the PCIE_MSI_INTR0_MASK|ENABLE setting is lost, we need to resume the > mask to the one before suspending. For PCIE_MSI_INTR0_ENABLE register(s), > since it's always 0xffffffff, so current code is fine. > > > Maybe we need to write suspend/resume hooks for the dwc core instead > > of moving code around to fix these bugs ? > > > > Even with suspend/resume hooks, we still need to fix the > PCIE_MSI_INTR0_MASK wrong setting with always ~0. After the fix, msi works > so we don't need suspend/resume hooks any more. I don't understand. The fix removes code that is writing into PCIE_MSI_INTR0_MASK (in dw_pcie_setup_rc()). Where that register content is restored on power up to the correct value then ? I assume those registers when the IP loses power are reset to their reset value, so something does not add up. Lorenzo
