On Sun, 2013-03-10 at 22:12 +0100, Loic Domaigne wrote: > On Fri, Mar 08, 2013 at 04:28:59PM -0600, Dan Williams wrote: > > On Fri, 2013-03-08 at 22:03 +0100, Loic Domaigne wrote: > > > > > > +/* maximum Rx URB size */ > > > +/* > > > + * in the original Linux driver, the rx urb size can be up to > > > + * CDC_NCM_NTB_MAX_SIZE_RX. > > > + * > > > + * Under VMware (as of wks9), URB size greater than 16kB is a problem, > > > + * so simply adjust this define when the driver is compiled for a VMware > > > + * environment. > > > + * > > > + */ > > > +#ifdef VMWARE_BUG > > > +#warning "Compiling for VMware" > > > +#define CDC_NCM_MAX_RX_URB_SIZE 16384 > > > +#else > > > +#define CDC_NCM_MAX_RX_URB_SIZE CDC_NCM_NTB_MAX_SIZE_RX > > > +#endif > > > > I can't see how that is going to get past any sort of review. Either > > there's some other way of detecting that the CPU is the VMWare emulated > > one or you're stuck with the bug until VMWare fixes it. > > Yeah, I know. > > The kludge consists to (re)compile the kernel module on the VMWare guest with > the VMWARE_BUG compiler flag set. > > We have a helper script for that task, but it's distros specific. We can > detect automatically a VMWare emulated CPU in some cases, but not always. > As a result, we end up sometimes asking the user. > > I am aware that it's not suitable as a generic solution. But waiting a fix > from VMWare might not be practical for you either. > > Any better ideas? Example from drivers/misc/vmw_balloon.c: #include <asm/hypervisor.h> ... /* * Check if we are running on VMware's hypervisor and bail out * if we are not. */ if (x86_hyper != &x86_hyper_vmware) return -ENODEV; Obviously for a non-x86-specific driver this needs to be conditional on #ifdef CONFIG_X86. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
