We shouldn't assume that a DriverBindingStart() can only start on a handle with device path installed. DevicePath protocol is just a special protocol. It's possible that a bus driver starts on a host controller handle and creates multiple children, each with only a Specific_IO protocol installed. Certain device driver can start on the children handle and open the Specific_IO protocol BY_DRIVER. I am not sure if certain today's network drivers may work like this. It's allowed per UEFI spec.
Thanks, Ray > -----Original Message----- > From: vit9696 <vit9...@protonmail.com> > Sent: Monday, January 13, 2020 5:20 PM > To: Gao, Zhichao <zhichao....@intel.com> > Cc: devel@edk2.groups.io; Ni, Ray <ray...@intel.com> > Subject: Re: [edk2-devel] [PATCH 1/1] ShellPkg: Do not connect handles > without device paths > > Hi, > > ‘Freeze’ means it is hung up forever, and we believe it is caused by an > invalid memory access in the firmware code. > > Using loading command with ‘-nc’ (no connect) will work fine, but that is > kind of expected, as the issue is caused exactly by > the connect logic. > > We do not believe it is possible for device controller to exist without a > device path protocol in the wild. Would you please > provide an example? If there is something we do not know about, I can imagine > introducing a PCD for this logic. > > Best wishes, > Vitaly > > > 13 янв. 2020 г., в 11:11, Gao, Zhichao <zhichao....@intel.com> написал(а): > > > > > > Hi, > > > > What does 'freeze' mean? System blocked for a while or it hung up forever? > > > > The change would affect the operation of the 'load' command. If some > > drivers need to connect to the device controller > but it doesn't have a device path protocol, the behavior of 'load' may be > incorrect. > > Is the option '-nc' working for your request? > > > > Thanks, > > Zhichao > > > >> -----Original Message----- > >> From: devel@edk2.groups.io [mailto:devel@edk2.groups.io] On Behalf Of > >> Vitaly Cheptsov via Groups.Io > >> Sent: Monday, January 13, 2020 5:39 AM > >> To: devel@edk2.groups.io > >> Subject: [edk2-devel] [PATCH 1/1] ShellPkg: Do not connect handles without > >> device paths > >> > >> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2460 > >> > >> Doing this reduces the amount of needless work during device connection > >> and resolves issues with firmwares that freeze when connecting handles > >> without device paths. > >> > >> Signed-off-by: Vitaly Cheptsov <vit9...@protonmail.com> > >> --- > >> ShellPkg/Library/UefiShellLevel2CommandsLib/Load.c | 4 ++-- > >> 1 file changed, 2 insertions(+), 2 deletions(-) > >> > >> diff --git a/ShellPkg/Library/UefiShellLevel2CommandsLib/Load.c > >> b/ShellPkg/Library/UefiShellLevel2CommandsLib/Load.c > >> index b6e7c952fa..083aac0dba 100644 > >> --- a/ShellPkg/Library/UefiShellLevel2CommandsLib/Load.c > >> +++ b/ShellPkg/Library/UefiShellLevel2CommandsLib/Load.c > >> @@ -32,8 +32,8 @@ ConnectAllEfi ( > >> UINTN Index; > >> > >> Status = gBS->LocateHandleBuffer ( > >> - AllHandles, > >> - NULL, > >> + ByProtocol, > >> + &gEfiDevicePathProtocolGuid, > >> NULL, > >> &HandleCount, > >> &HandleBuffer > >> -- > >> 2.21.0 (Apple Git-122.2) > >> > >> > >> -=-=-=-=-=-= > >> Groups.io Links: You receive all messages sent to this group. > >> > >> View/Reply Online (#53170): https://edk2.groups.io/g/devel/message/53170 > >> Mute This Topic: https://groups.io/mt/69653841/1768756 > >> Group Owner: devel+ow...@edk2.groups.io > >> Unsubscribe: https://edk2.groups.io/g/devel/unsub > >> [zhichao....@intel.com] > >> -=-=-=-=-=-= > > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#53188): https://edk2.groups.io/g/devel/message/53188 Mute This Topic: https://groups.io/mt/69653841/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
