[SLOF] [PATCH] fat-files: Fix bug with root-entries = 0 on certain FAT32 file systems

Alexey Kardashevskiy aik at ozlabs.ru
Wed Dec 9 15:53:28 AEDT 2015

On 12/03/2015 07:42 AM, Thomas Huth wrote:
> On 02/12/15 16:39, Thomas Huth wrote:
>> The maximum number of root directory entries can be zero on
>> certain FAT32 file systems. In this case, we've got to read
>> the cluster number of the root directory from the extended BPB
>> instead. See also the following URL for details:
>> https://en.wikipedia.org/wiki/Design_of_the_FAT_file_system#BPB20_OFS_06h
> Forgot to say: With that patch, I was able to boot from a pass-through
> USB stick that was formatted with FAT32.
> However, there are some additional messages from libusb showing up:
> Scanning USB
>    XHCI: Initializing
> ptr 0x7E4E8019 desc_type 48
> ptr 0x7E4E8026 desc_type 48
>      USB Storage
>         SCSI: Looking for devices
>            101000000000000 DISK     : "SanDisk Ultra Fit 1.00"
> ... if I get that "desc_type 48" right, this means that libusb can not
> handle "SuperSpeed Endpoint Companion Descriptor" yet? Is this something
> to worry about or just harmless debug messages?

I have no idea :)
But I applied this anyway, thanks.


More information about the SLOF mailing list