Re: [PATCH] rtlwifi: rtl8192cu: Fix NULL dereference BUG when using new_id

On Wed, 2013-02-06 at 01:16 +0000, Ben Hutchings wrote:

quoted

I don't know why USB differs from PCI, but we do need the dynamic ID here as 
there are always new IDs being issued. One of the criteria for adding the ID to 
the table is that it works OK with dynamic addition. These devices are 
frequently reported by users that do not have the skills to build their own kernel.

But since there is no way to set the driver_info for a new USB ID
(again, unlike PCI), your change will reject all dynamic IDs.  (And in
any case, if the USB core were changed to allow setting driver_info,
userland would have difficulty providing a valid pointer!)

It looks like the driver_info is really driver-specific data used to
share a probe function between multiple drivers.  But you could add
per-driver probe functions that pass the correct rtl_hal_cfg as an extra
argument to rtl_usb_probe(), and then dynamic IDs should work.

Some (PCI?) drivers had/have numbers instead of pointers, so userland
can provide a number and it then looks up the pointer in an array.
That's only slightly indirected but makes new_id more useful in that
case.

johannes

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