Hi Ray,
On September 15, 2017 12:33:04 AM GMT-03:00, "Ni, Ruiyu" <[email protected]> wrote: >Paulo, >Before raising my questions, I'd like to confirm that for a single >CD/DVD in UDF format, there might be multiple volumes. >One of the volume could be Eltorito type. >If my understanding is correct, please continue reading below. Right. > >We found below mapping table using "map -r" shell command in a platform >with only PartitionDxe change and without UdfDxe driver. >It's a bug that <BLK6> and <BLK7/FS2> are created. Actually they are >identical to <BLK3> and <BLK4/FS1>. > >--- Mapping table--- > BLK2: Alias(s): > PciRoot(0x0)/Pci(0x1F,0x2)/Sata(0x0,0xFFFF,0x0) > > BLK3: Alias(s): > PciRoot(0x0)/Pci(0x1F,0x2)/Sata(0x0,0xFFFF,0x0)/CDROM(0x0) > FS1: Alias(s):CD1a65535a1:;BLK4: > PciRoot(0x0)/Pci(0x1F,0x2)/Sata(0x0,0xFFFF,0x0)/CDROM(0x1) > > BLK5: Alias(s): >PciRoot(0x0)/Pci(0x1F,0x2)/Sata(0x0,0xFFFF,0x0)/VenMedia(C5BD4D42-1A76-4996-8956-73CDA326CD0A) > BLK6: Alias(s): >PciRoot(0x0)/Pci(0x1F,0x2)/Sata(0x0,0xFFFF,0x0)/VenMedia(C5BD4D42-1A76-4996-8956-73CDA326CD0A)/CDROM(0x0) > FS2: Alias(s):CD1a65535ab:;BLK7: >PciRoot(0x0)/Pci(0x1F,0x2)/Sata(0x0,0xFFFF,0x0)/VenMedia(C5BD4D42-1A76-4996-8956-73CDA326CD0A)/CDROM(0x1) >--- End of mapping table --- > >After investigation, I found the UDF logic in Partition driver doesn't >truly skip the Eltorito volume. >The code flow is like below: > > 1. <BLK2> is created by ScsiDiskDxe driver. > 2. By passing <BLK2> to PartitionDxe Start() >* <BLK3> and <BLK4/FS1> are created by PartitionDxe driver, by >PartitionInstallElToritoChildHandles(). >* <BLK5> is created by PartitionDxe driver, by >PartitionInstallUdfChildHandles(). > 3. By passing <BLK5> to PartitionDxe Start() >* <BLK6> and <BLK7/FS2> are created by PartitionDxe driver, by >PartitionInstallElToritoChildHandles(). > >I think step 2.a is not correct if my understanding to UDF is correct. >The PartitionInstallUdfChildHandles() should iterate >all volumes in the media and creates the child BLK handle for each >volume, but skipping Eltorito volume. > >Instead, the current implementation just creates one child BLK handle >for the entire media. >To avoid reclusively creating child BLK handle, the >PartitionInstallUdfChildHandles() contains a logic to do nothing when >the handle is created by ParititonDxe driver. The logic is not needed >when the implementation follows my suggestion above. >Due to this, step 3.a creates the additional but shouldn't-exist BLK >handles <BLK6> and <BLK7/FS2>. > >UdfDxe driver is supposed to Start() on each volume and produce >SimpleFileSystem protocol. It seems that PartitionInstallUdfChildHandles() indeed skips the ElTorito partitions otherwise you'd see the ".../CDROM(0x1)/VenMedia()" and ".../CDROM(0x0)/VenMedia()" device paths *also* in the mapping output. If I understand correctly, the problem is that when we create a child handle for an UDF volume, Partition driver will execute again, parse the newly created UDF handle, find again an ElTorito partition and then install a new child handle (VenMedia()/CDROM()) So, the logic of skipping of ElTorito partitions in PartitionInstallUdfChildHandles() is not enough. Unfortunately we can't handle UDF bridge disks (ElTorito + UDF) entirely in PartitionInstallUdfChildHandles() -- we should probably also skip UDF device paths in PartitionInstallElToritoChildHandles(). Does it make sense to you, Ray? Thanks for raising this up. Paulo > >Do you agree with my above suggestions? > >Laszlo, >I understood your needs of this UDF support. But as you can see there >are many build failures and even functionality issues due to this >support. >I am not sure how the other open source project handles such cases. >But I am thinking maybe we could move the whole UDF support to >edk2-staging firstly and move it back after all the issues are >resolved. >What's your suggestion? > >Thanks/Ray -- Sent from my Android device with K-9 Mail. Please excuse my brevity. _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
