Hi, Hao,Liming,

this is my reply， function XhcInitializeDeviceSlot64 will init EndpointTransferRing,while fuctionUsbMassReadBlocks return (Invalid Parameter), which result in run function UsbMassReset, this will call XhcDisableSlotCmd64, will clear EndpointTransferRing, like this Xhc->UsbDevContext[SlotId].EndpointTransferRing[Index] = NULL; If fuctionUsbMassReadBlocks return success also run function UsbMassReset, will hang for the same reason. why fuctionUsbMassReadBlocks return (Invalid Parameter), this function will call UsbBootRequestSense,this retun (Invalid Parameter). At the same time, Ehci also retun (Invalid Parameter).

Thanks

-----原始邮件-----
发件人: "Wu, Hao A" <hao.a.wu@intel.com>
发送时间: 2023-07-25 10:18:42 (星期二)
收件人: "Gao, Liming" <gaoliming@byosoft.com.cn>, "devel@edk2.groups.io" <devel@edk2.groups.io>, "sulikun@loongson.cn" <sulikun@loongson.cn>, "Demeter, Miki" <miki.demeter@intel.com>
主题: RE: [edk2-devel] empty USB DVD disk hang Xhci

Sorry, I do not have much resource to review this in detail. But the patch generally looks good to me:

Acked-by: Hao A Wu hao.a.wu@intel.com

However, I hope the below question can be answered (or add related information to the commit log message) before mering:

Likun, could you help to elaborate a bit more on why the below statement will return NULL pointer for “USB DVD with empty disk”?

EPRing        = (TRANSFER_RING *)(UINTN)Xhc->UsbDevContext[SlotId].EndpointTransferRing[Dci-1];

Best Regards,

Hao Wu

From: gaoliming <gaoliming@byosoft.com.cn>
Sent: Tuesday, July 25, 2023 9:44 AM
To: devel@edk2.groups.io; sulikun@loongson.cn; Demeter, Miki <miki.demeter@intel.com>
Cc: Wu, Hao A <hao.a.wu@intel.com>
Subject: 回复: [edk2-devel] empty USB DVD disk hang Xhci

Likun:

This change is good to me. Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>

Hao:

Have you time to review this fix?

Thanks

Liming

发件人: devel@edk2.groups.io <devel@edk2.groups.io> 代表苏丽坤
发送时间: 2023年7月18日 9:49
收件人: gaoliming@byosoft.com.cn; miki.demeter@intel.com; devel@edk2.groups.io
主题: [edk2-devel] empty USB DVD disk hang Xhci

Hi

   We find a bug in xhci, USB DVD boot with emtpy disk will hang Xhci while Ehci can pass.

    The hang log is shown as : MdeModulePkg/Bus/Pci/XhciDxe/XhciSched.c(1847): TrsRing != ((void *) 0)

    We suggest a way to solve this bug is shown as: https://github.com/suling-123/edk2 the latest commit, MdeModulePkg: Solve boot hang xhci driver when use USB DVD with empty disk, 950bc8781d81b96b0c7944e7ac947382b1bc0c06

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