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From: Takashi Iwai <>
To: Greg Kroah-Hartman <>
Cc: Mathias Nyman <>,
	Moritz Fischer <>,,
Subject: Re: [PATCH] usb: renesas-xhci: Prefer firmware loading on unknown ROM state
Date: Thu, 26 Aug 2021 13:55:54 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <YSd/>

On Thu, 26 Aug 2021 13:50:13 +0200,
Greg Kroah-Hartman wrote:
> On Thu, Aug 19, 2021 at 01:34:27PM +0200, Takashi Iwai wrote:
> > The recent attempt to handle an unknown ROM state in the commit
> > d143825baf15 ("usb: renesas-xhci: Fix handling of unknown ROM state")
> > resulted in a regression and reverted later by the commit 44cf53602f5a
> > ("Revert "usb: renesas-xhci: Fix handling of unknown ROM state"").
> > The problem of the former fix was that it treated the failure of
> > firmware loading as a fatal error.  Since the firmware files aren't
> > included in the standard linux-firmware tree, most users don't have
> > them, hence they got the non-working system after that.  The revert
> > fixed the regression, but also it didn't make the firmware loading
> > triggered even on the devices that do need it.  So we need still a fix
> > for them.
> > 
> > This is another attempt to handle the unknown ROM state.  Like the
> > previous fix, this also tries to load the firmware when ROM shows
> > unknown state.  In this patch, however, the failure of a firmware
> > loading (such as a missing firmware file) isn't handled as a fatal
> > error any longer when ROM has been already detected, but it falls back
> > to the ROM mode like before.  The error is returned only when no ROM
> > is detected and the firmware loading failed.
> > 
> > Along with it, for simplifying the code flow, the detection and the
> > check of ROM is factored out from renesas_fw_check_running() and done
> > in the caller side, renesas_xhci_check_request_fw().  It avoids the
> > redundant ROM checks.
> > 
> > The patch was tested on Lenovo Thinkpad T14 gen (BIOS 1.34).  Also it
> > was confirmed that no regression is seen on another Thinkpad T14
> > machine that has worked without the patch, too.
> > 
> > Fixes: 44cf53602f5a ("Revert "usb: renesas-xhci: Fix handling of unknown ROM state"")
> > BugLink:
> > Signed-off-by: Takashi Iwai <>
> > ---
> >  drivers/usb/host/xhci-pci-renesas.c | 35 +++++++++++++++++++----------
> >  1 file changed, 23 insertions(+), 12 deletions(-)
> This does not apply to my usb-linus branch, are you sure it is still
> needed in Linus's tree right now?

I guess we can postpone for 5.15.  The patch was written for the code
on linux-next, and I see there have been a few code clean up there.

But the patch itself could be applied to Linus tree with a slight
fuzz, so the stable backport should be fine.

If it's still not cleanly applicable, let me know.  I'll refresh the
patch for whatever preferred branch.



  reply	other threads:[~2021-08-26 11:55 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-19 11:34 Takashi Iwai
2021-08-26 10:28 ` Takashi Iwai
2021-08-26 11:08   ` Greg Kroah-Hartman
2021-08-26 11:50 ` Greg Kroah-Hartman
2021-08-26 11:55   ` Takashi Iwai [this message]
2021-08-26 12:21     ` Greg Kroah-Hartman
2021-08-26 12:37       ` Takashi Iwai

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