> -----Original Message----- > From: Limonciello, Mario > Sent: Friday, October 4, 2019 9:06 AM > To: 'Yehezkel Bernat'; Mika Westerberg > Cc: linux-usb@xxxxxxxxxxxxxxx; Andreas Noever; Michael Jamet; Rajmohan Mani; > nicholas.johnson-opensource@xxxxxxxxxxxxxx; Lukas Wunner; > gregkh@xxxxxxxxxxxxxxxxxxx; stern@xxxxxxxxxxxxxxxxxxx; Anthony Wong; LKML > Subject: RE: [RFC PATCH 17/22] thunderbolt: Add initial support for USB4 > > > > > On Fri, Oct 4, 2019 at 11:19 AM Mika Westerberg > > <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > > > > > > On Fri, Oct 04, 2019 at 11:07:34AM +0300, Yehezkel Bernat wrote: > > > > > Also if you can get the hw_vendor_id and hw_product_id from the kernel > > > > > does that mean you don't need to do the two reads or you still need > > > > > those? > > > > > > > > Are those the chip vendor or the OEM, in case they are different? > > > > > > Those are the actual USB4 hardware maker values, directly from > > > ROUTER_CS_0 (p. 287 in the USB4 spec). This almost certainly differ from > > > the OEM values from DROM we currently expose. > > > > Makes sense to me. Userspace can learn the relevant IDs that their NVM > format > > is > > known. > > > > > > > > > Thinking about it again, I'd guess it shouldn't matter much, if the chip is from > > > > Intel, the FW supports NVM upgrade, isn't it? > > > > > > So the bottom line is that if the kernel thinks the router supports NVM > > > upgrade it exposes the nvm_active/nvm_non_active files etc. I think > > > fwupd uses this information to display user whether the device can be > > > upgraded or not (for example ICL cannot as the NVM is part of BIOS). > > > > Yes, fwupd already takes this into account, but the question here is how to > > handle cases that NVM is available but the format isn't known to > > userspace (yet). > > Exactly. > > > > > > > > > Exposing hw_vendor_id and hw_product_id may speed up fwupd because it > > > does not need to go over the active NVM to figure out whether the new > > > image is for the correct controller. > > > > It's not about finding the relevant image for upgrade (which must be searched > > for by looking in the DROM vendor/product values), but about the question if > the > > NVM format is known to userspace and skip the parsing work if it's anyway > going > > to fail. > > > > So yes, I think exposing vendor ID (and maybe also product ID) can improve the > > situation. > > > > Currently at probe time everything comes from udev except for the bit indicating > running in "native" mode or not. Just enough chunks of the NVM are read to > determine > that (IE no reading up through DROM or jumping around). > > If Christian's patch to export generation is accepted I think that we could move > that check > to only read -native if generation < 3. > Sorry for the typo; generation < 4. > And if you export the hw_vendor_id and hw_product_id fields then that means > USB4 devices > would require no reading from NVM at "probe" since we don't have to read a - > native bit. > > We would still of course read and analyze the NVM when it comes time to flash a > new device > though.
