> -----Original Message----- > From: Roedel, Joerg [mailto:[email protected]] > Sent: Thursday, April 07, 2011 3:51 PM > To: Alan Stern > Cc: Greg Kroah-Hartman; Sarah Sharp; Xu, Andiry; [email protected]; > [email protected]; [email protected] > Subject: Re: [PATCH] USB host: Fix lockdep warning in AMD PLL quirk > > On Wed, Apr 06, 2011 at 11:16:07AM -0400, Alan Stern wrote: > > On Wed, 6 Apr 2011, Joerg Roedel wrote: > > > The counter really should be a bool: Has the chipset already been > > probed or not? After all, nobody cares how many times this routine was > > called. > > > > > + spin_unlock_irqrestore(&amd_lock, flags); > > > > This code now contains a bug: You incremented the probe_count _before_ > > doing the probe. If another thread calls this routine right now, it > > will get an incorrect result. > > > > Fixing this up should be fairly easy. > > Hmm, we can get rid of the amd_lock completly if every thread uses the > following call-order: > > usb_amd_find_chipset_info(); > usb_amd_quirk_pll_enable(); > usb_amd_quirk_pll_disable(); > usb_amd_dev_put(); >
The correct order is: usb_amd_find_chipset_info(); usb_amd_quirk_pll_disable(); usb_amd_quirk_pll_enable(); usb_amd_dev_put(); The pair of pll disable and enable may be called for multiple times. Thanks, Andiry _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
