lkml.org 
[lkml]   [2013]   [Jul]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] usb: dwc3: core: modify IO memory resource after deferred probe completes
Hi,

On Fri, Jul 26, 2013 at 09:48:26AM +0300, Ivan T. Ivanov wrote:
> > > Also, this is not *modifying* what was passed, just skipping the xHCI
> > > address space so we don't request_mem_region() an area we won't really
> > > handle and prevent xhci-hcd.ko from probing.
> >
> > Hmm? platform_get_resource() returns a pointer to an entry in the
> > platform_device's resource[] array. And "res->start +=" modifies the
> > entry pointed at. If it didn't, the bug fixed by this patch wouldn't
> > have happened.
> >
> > Are you sure this code will work OK if you build the driver as a module,
> > modprobe it, rmmod it, and then modprobe it again? Seems like it won't,
> > unless the dev->resource[] array gets reinitialized in between somehow.

gotta try that one... Perhaps the correct way would be to copy the
resource to a private struct resource and modify that one, leaving
pdev->resources untouched.

> In addition, I think driver is wasting memory, because on every probe
> it will reallocate driver state variable. This also happens in several
> other drivers which are using deferred probe.

We can't do much about this since we're using devm_* API. Perhaps
deferred probe should make sure to destroy the device and add it back
later ? Otherwise what's the benefit of using devm_* ?

--
balbi
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2013-07-26 12:21    [W:0.226 / U:0.200 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site