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Mon, 13 Jul 2026 09:18:38 -0700 (PDT) Date: Mon, 13 Jul 2026 12:18:36 -0400 From: Alan Stern To: Daniel Palmer Cc: peter.chen@kernel.org, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 1/2] usb: ehci: Add option to override ehci_readl()/ehci_writel() Message-ID: <6883bde1-e2f0-40d5-8f98-1857073ec9ed@rowland.harvard.edu> References: <20260713122205.1350933-1-daniel@thingy.jp> <20260713122205.1350933-2-daniel@thingy.jp> <02d6c843-6606-4f67-aef7-3a88846d6388@rowland.harvard.edu> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Jul 14, 2026 at 12:07:11AM +0900, Daniel Palmer wrote: > Hi Alan, > > On Mon, 13 Jul 2026 at 23:46, Alan Stern wrote: > > > > On Mon, Jul 13, 2026 at 11:37:19PM +0900, Daniel Palmer wrote: > > > Hi Alan, > > > > > > On Mon, 13 Jul 2026 at 23:21, Alan Stern wrote: > > > > > +config HAVE_BROKEN_EHCI_HCD > > > > > + bool > > > > > > > > That is not a good choice of name; it's far too generic. EHCI > > > > controllers can be broken in so many different ways... > > > > > > > > How about USB_EHCI_MMIO_OVERRIDES instead? > > > > > > Noted. Based on that we'd have a config for each piece that needs to > > > be overridden so drivers can pick the ones they need? > > > > Maybe. What other things will need to be overridden? It's hard to tell > > what you're planning from just a single sample. > > For the fotg210 at least the location of the port status register > needs to be overridden, it doesn't support sITDs so that has to be > blocked, and the hardware has a bug where the length of ITDs is broken > so it needs to have a workaround to write the value it wants. Okay. I think it makes sense to have a separate CONFIG flag for each of these. Alan Stern