Hi Paulo, The responsibility of PartitionDxe driver is to partition the physical BLK (the entire CDROM) into logical BLKs (one BLK for each volume). It doesn't make sense to create a child BLK handle which still covers the entire CDROM. So as I suggested in below, PartitionInstallUdfChildHandles() should contain a for-loop to iterate all the volumes in the CDROM, and create child BLK handle for each volumes, but skipping Eltorito volume.
Thanks/Ray > -----Original Message----- > From: Paulo Alcantara [mailto:[email protected]] > Sent: Friday, September 15, 2017 12:58 PM > To: Ni, Ruiyu <[email protected]>; Laszlo Ersek <[email protected]> > Cc: [email protected]; Wu, Hao A <[email protected]>; Zeng, Star > <[email protected]> > Subject: Re: Functionality issues in UDF support > > > > 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
