linux-kernel - RE: [Intel-gfx] [PATCH v10 3/5] mei: gsc: setup char driver alive in spite of firmware handshake failure

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Message-ID: <MW3PR11MB4651F1ABDD3C5A838A6A8440ED0E9@MW3PR11MB4651.namprd11.prod.outlook.com>
Date:   Sun, 13 Mar 2022 12:12:21 +0000
From:   "Usyskin, Alexander" <alexander.usyskin@...el.com>
To:     "Ceraolo Spurio, Daniele" <daniele.ceraolospurio@...el.com>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        "Vivi, Rodrigo" <rodrigo.vivi@...el.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        "Tvrtko Ursulin" <tvrtko.ursulin@...ux.intel.com>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Winkler, Tomas" <tomas.winkler@...el.com>,
        "Lubart, Vitaly" <vitaly.lubart@...el.com>,
        "intel-gfx@...ts.freedesktop.org" <intel-gfx@...ts.freedesktop.org>
Subject: RE: [Intel-gfx] [PATCH v10 3/5] mei: gsc: setup char driver alive in
 spite of firmware handshake failure



> -----Original Message-----
> From: Ceraolo Spurio, Daniele <daniele.ceraolospurio@...el.com>
> Sent: Thursday, March 10, 2022 02:28
> To: Usyskin, Alexander <alexander.usyskin@...el.com>; Greg Kroah-
> Hartman <gregkh@...uxfoundation.org>; Jani Nikula
> <jani.nikula@...ux.intel.com>; Joonas Lahtinen
> <joonas.lahtinen@...ux.intel.com>; Vivi, Rodrigo <rodrigo.vivi@...el.com>;
> David Airlie <airlied@...ux.ie>; Daniel Vetter <daniel@...ll.ch>; Tvrtko
> Ursulin <tvrtko.ursulin@...ux.intel.com>
> Cc: linux-kernel@...r.kernel.org; Winkler, Tomas
> <tomas.winkler@...el.com>; Lubart, Vitaly <vitaly.lubart@...el.com>; intel-
> gfx@...ts.freedesktop.org
> Subject: Re: [Intel-gfx] [PATCH v10 3/5] mei: gsc: setup char driver alive in
> spite of firmware handshake failure
> 
> 
> 
> On 3/8/2022 8:36 AM, Alexander Usyskin wrote:
> > Setup char device in spite of firmware handshake failure.
> > In order to provide host access to the firmware status registers and other
> > information required for the manufacturing process.
> 
> IMO this patch should be moved to after the patch that adds the logic to
> fetch the FW version, as that is interesting info for sysfs. Not a blocker.
> 

Actually, the FW version is filled only if there is an established channel with FW.
Firmware status registers are the crucial information for debug, and it filled
in previous patches.

-- 
Thanks,
Sasha


> >
> > Signed-off-by: Alexander Usyskin <alexander.usyskin@...el.com>
> > Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
> 
> Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@...el.com>
> 
> Daniele
> 
> > ---
> >   drivers/misc/mei/gsc-me.c | 11 ++++++-----
> >   1 file changed, 6 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/misc/mei/gsc-me.c b/drivers/misc/mei/gsc-me.c
> > index 0afae70e0609..cf427f6fdec9 100644
> > --- a/drivers/misc/mei/gsc-me.c
> > +++ b/drivers/misc/mei/gsc-me.c
> > @@ -79,11 +79,12 @@ static int mei_gsc_probe(struct auxiliary_device
> *aux_dev,
> >   	pm_runtime_set_active(device);
> >   	pm_runtime_enable(device);
> >
> > -	if (mei_start(dev)) {
> > -		dev_err(device, "init hw failure.\n");
> > -		ret = -ENODEV;
> > -		goto err;
> > -	}
> > +	/* Continue to char device setup in spite of firmware handshake
> failure.
> > +	 * In order to provide access to the firmware status registers to the
> user
> > +	 * space via sysfs.
> > +	 */
> > +	if (mei_start(dev))
> > +		dev_warn(device, "init hw failure.\n");
> >
> >   	pm_runtime_set_autosuspend_delay(device,
> MEI_GSC_RPM_TIMEOUT);
> >   	pm_runtime_use_autosuspend(device);