Laszlo Ersek 76fd5a660d MdeModulePkg/AtaAtapiPassThru: disable only BM-DMA at ExitBootServices() ... 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 issue (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: 6fb8ddd36b Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Tested-by: dann frazier <dann.frazier@canonical.com> Reviewed-by: Star Zeng <star.zeng@intel.com> Tested-by: Aleksei Kovura <alex3kov@zoho.com>		2017-10-27 18:05:07 +02:00
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AtaAtapiPassThru	MdeModulePkg/AtaAtapiPassThru: disable only BM-DMA at ExitBootServices()	2017-10-27 18:05:07 +02:00
AtaBusDxe	MdeModulePkg/Bus: Fix typos in comments	2016-10-27 09:11:16 +08:00