Re: [PATCH] MdeModulePkg/AtaAtapiPassThru: disable only BM-DMA at ExitBootServices()

["Ni, Ruiyu" <ruiyu.ni@intel.com>]

I cannot explain precisely why the S4 resume fails.
I can just guess: Windows might have some assumptions on the BM bit.

Thanks/Ray

> -----Original Message-----
> From: Zeng, Star
> Sent: Wednesday, November 22, 2017 6:26 PM
> To: Ni, Ruiyu <ruiyu.ni@intel.com>; Laszlo Ersek <lersek@redhat.com>;
> edk2-devel-01 <edk2-devel@lists.01.org>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>; Dong, Eric
> <eric.dong@intel.com>; Dann Frazier <dannf@ubuntu.com>; Zeng, Star
> <star.zeng@intel.com>
> Subject: RE: [edk2] [PATCH] MdeModulePkg/AtaAtapiPassThru: disable only
> BM-DMA at ExitBootServices()
> 
> Ray,
> 
> You may explain more why Win10 S4 resume fails with only BM disabled,
> then Laszlo can know the issue well.
> 
> 
> Thanks,
> Star
> -----Original Message-----
> From: Ni, Ruiyu
> Sent: Wednesday, November 22, 2017 6:06 PM
> To: Laszlo Ersek <lersek@redhat.com>; edk2-devel-01 <edk2-
> devel@lists.01.org>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>; Dong, Eric
> <eric.dong@intel.com>; Zeng, Star <star.zeng@intel.com>; Dann Frazier
> <dannf@ubuntu.com>
> Subject: RE: [edk2] [PATCH] MdeModulePkg/AtaAtapiPassThru: disable only
> BM-DMA at ExitBootServices()
> 
> Laszlo,
> Our QA found Win10 S4 resume fails due to your change.
> As you might notice that I just rolled back the BM disabling patches in PciBus
> module, I am thinking about maybe you need to rollback the whole
> ExitBootServices callback as well to fix the compatibility issue.
> 
> Thanks/Ray
> 
> > -----Original Message-----
> > From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> > Laszlo Ersek
> > Sent: Saturday, October 28, 2017 12:10 AM
> > To: edk2-devel-01 <edk2-devel@lists.01.org>
> > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>; Dong, Eric
> > <eric.dong@intel.com>; Zeng, Star <star.zeng@intel.com>; Dann Frazier
> > <dannf@ubuntu.com>
> > Subject: Re: [edk2] [PATCH] MdeModulePkg/AtaAtapiPassThru: disable
> > only BM-DMA at ExitBootServices()
> >
> > On 10/26/17 17:48, Laszlo Ersek wrote:
> > > Clearing I/O port decoding in the PCI command register at
> > > ExitBootServices() breaks IDE boot in Windows, on QEMU's "pc"
> > > (i440fx) machine type. (AHCI boot on "q35" is unaffected.) Windows
> > > seems repeatedly stuck, apparently waiting for a timeout of sorts.
> > >
> > > This is arguably a Windows bug; a native OS driver should not expect
> > > the firmware to leave the PCI command register in any particular state.
> > >
> > > Strictly speaking, we only need to disable BM-DMA at
> > > ExitBootServices(), in order to abort pending transfers to/from RAM,
> > > which is soon to be owned by the OS. BM-DMA is also the only bit
> > > that's explicitly named by the UEFI Driver Writers' Guide, for
> > > clearing at
> > ExitBootServices().
> > >
> > > I've verified that clearing only BM-DMA fixes the isse (boot time)
> > > on i440fx, and does not regress q35/AHCI.
> > >
> > > Cc: Aleksei Kovura <alex3kov@zoho.com>
> > > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > > Cc: Dann Frazier <dannf@ubuntu.com>
> > > Cc: Eric Dong <eric.dong@intel.com>
> > > Cc: Star Zeng <star.zeng@intel.com>
> > > Reported-by: Aleksei Kovura <alex3kov@zoho.com>
> > > Reported-by: Dann Frazier <dannf@ubuntu.com>
> > > Reported-by: https://launchpad.net/~cjkrupp
> > > Bisected-by: Dann Frazier <dannf@ubuntu.com>
> > > Bisected-by: https://launchpad.net/~cjkrupp
> > > Suggested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > > Suggested-by: Star Zeng <star.zeng@intel.com>
> > > Ref: https://bugs.launchpad.net/ubuntu/+source/edk2/+bug/1725560
> > > Fixes: 6fb8ddd36bde45614b0a069528cdc97077835a74
> > > Contributed-under: TianoCore Contribution Agreement 1.1
> > > Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> > > ---
> > >
> > > Notes:
> > >     Repo:   https://github.com/lersek/edk2.git
> > >     Branch: ata_disable_only_bmdma
> > >
> > >  MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.h | 3 +--
> > > MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.c | 5 ++---
> > >  2 files changed, 3 insertions(+), 5 deletions(-)
> > >
> > > diff --git
> > > a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.h
> > > b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.h
> > > index 8d6eac706c0b..92c5bf2001cd 100644
> > > --- a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.h
> > > +++ b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.h
> > > @@ -123,8 +123,7 @@ typedef struct {
> > >    LIST_ENTRY                        NonBlockingTaskList;
> > >
> > >    //
> > > -  // For disabling the device (especially Bus Master DMA) at
> > > -  // ExitBootServices().
> > > +  // For disabling Bus Master DMA on the device at ExitBootServices().
> > >    //
> > >    EFI_EVENT                         ExitBootEvent;
> > >  } ATA_ATAPI_PASS_THRU_INSTANCE;
> > > diff --git
> > > a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.c
> > > b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.c
> > > index 09064dda18b7..e10e0d4e65f6 100644
> > > --- a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.c
> > > +++ b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.c
> > > @@ -480,8 +480,7 @@ InitializeAtaAtapiPassThru (  }
> > >
> > >  /**
> > > -  Disable the device (especially Bus Master DMA) when exiting the
> > > boot
> > > -  services.
> > > +  Disable Bus Master DMA on the device when exiting the boot services.
> > >
> > >    @param[in] Event    Event for which this notification function is being
> > >                        called.
> > > @@ -506,7 +505,7 @@ AtaPassThruExitBootServices (
> > >    PciIo->Attributes (
> > >             PciIo,
> > >             EfiPciIoAttributeOperationDisable,
> > > -           Instance->EnabledPciAttributes,
> > > +           Instance->EnabledPciAttributes &
> > > + EFI_PCI_IO_ATTRIBUTE_BUS_MASTER,
> > >             NULL
> > >             );
> > >  }
> > >
> >
> > Thanks Everyone for the feedback; I fixed the typo pointed out by Star
> > and pushed the patch as commit 76fd5a660d70.
> >
> > Cheers
> > Laszlo
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