linux-kernel - Re: [PATCH v19 2/9] usb: dwc3: core: Access XHCI address space temporarily to read port info

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Message-ID: <2024040558-undercut-sandbar-7ffc@gregkh>
Date: Fri, 5 Apr 2024 06:43:56 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Bjorn Andersson <quic_bjorande@...cinc.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
	Johan Hovold <johan@...nel.org>,
	Krishna Kurapati <quic_kriskura@...cinc.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Rob Herring <robh@...nel.org>,
	Bjorn Andersson <andersson@...nel.org>,
	Wesley Cheng <quic_wcheng@...cinc.com>,
	Konrad Dybcio <konrad.dybcio@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
	Felipe Balbi <balbi@...nel.org>, devicetree@...r.kernel.org,
	linux-arm-msm@...r.kernel.org, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org, quic_ppratap@...cinc.com,
	quic_jackp@...cinc.com, Johan Hovold <johan+linaro@...nel.org>
Subject: Re: [PATCH v19 2/9] usb: dwc3: core: Access XHCI address space
 temporarily to read port info

On Thu, Apr 04, 2024 at 06:25:48PM -0700, Bjorn Andersson wrote:
> On Thu, Apr 04, 2024 at 02:58:29PM +0200, Greg Kroah-Hartman wrote:
> > On Thu, Apr 04, 2024 at 10:07:27AM +0200, Krzysztof Kozlowski wrote:
> > > On 04/04/2024 09:21, Johan Hovold wrote:
> > > > On Thu, Apr 04, 2024 at 10:42:22AM +0530, Krishna Kurapati wrote:
> > > >  
> > > >> +static int dwc3_get_num_ports(struct dwc3 *dwc)
> > > >> +{
> > > >> +	void __iomem *base;
> > > >> +	u8 major_revision;
> > > >> +	u32 offset;
> > > >> +	u32 val;
> > > >> +
> > > >> +	/*
> > > >> +	 * Remap xHCI address space to access XHCI ext cap regs since it is
> > > >> +	 * needed to get information on number of ports present.
> > > >> +	 */
> > > >> +	base = ioremap(dwc->xhci_resources[0].start,
> > > >> +		       resource_size(&dwc->xhci_resources[0]));
> > > >> +	if (!base)
> > > >> +		return PTR_ERR(base);
> > > > 
> > > > This is obviously still broken. You need to update the return value as
> > > > well.
> > > > 
> > > > Fix in v20.
> > > 
> > > If one patchset reaches 20 versions, I think it is time to stop and
> > > really think from the beginning, why issues keep appearing and reviewers
> > > are still not happy.
> > > 
> > > Maybe you did not perform extensive internal review, which you are
> > > encouraged to by your own internal policies, AFAIR. Before posting next
> > > version, please really get some internal review first.
> > 
> > Also get those internal reviewers to sign-off on the commits and have
> > that show up when you post them next.  That way they are also
> > responsible for this patchset, it's not fair that they are making you do
> > all the work here :)
> > 
> 
> I like this idea and I'm open to us changing our way of handling this.
> 
> But unless such internal review brings significant input to the
> development I'd say a s-o-b would take the credit from the actual
> author.

It does not do that at all.  It provides proof that someone else has
reviewed it and agrees with it.  Think of it as a "path of blame" for
when things go bad (i.e. there is a bug in the submission.)  Putting
your name on it makes you take responsibility if that happens.

> We've discussed a few times about carrying Reviewed-by et al from the
> internal reviews, but as maintainer I dislike this because I'd have no
> way to know if a r-b on vN means the patch was reviewed, or if it was
> just "accidentally" carried from v(N-1).
> But it might be worth this risk, is this something you think would be
> appropriate?

For some companies we REQUIRE this to happen due to low-quality
submissions and waste of reviewer's time.  Based on the track record
here for some of these patchsets, hopefully it doesn't become a
requirement for this company as well :)

thanks,

greg k-h