Re: [PATCH v6 02/10] Revert "drm/qxl: do not run release if qxl failed to init"

[Thomas Zimmermann]

Hi Tong

Am 04.02.21 um 19:52 schrieb Tong Zhang:
> Hi Thomas,
>
> The original problem was qxl_device_init() can fail,
> when it fails there is no need to call
> 	qxl_modeset_fini(qdev);
> 	qxl_device_fini(qdev);
> But those two functions are otherwise called in the qxl_drm_release() -

OK, makes sense. Thanks for the explanation.

> I have posted an updated patch.
> The new patch use the following logic
>
> +	if (!qdev->ddev.mode_config.funcs)
> +	  return;

This is again just papering over the issue. Better don't call 
qxl_drm_release() in the error path if qxl_device_init() fails.

I see two solutions: either roll-back manually, or use our new managed 
DRM interfaces. This is what the other drivers do.

Best regards
Thomas

> 	qxl_modeset_fini(qdev);
> 	qxl_device_fini(qdev);
>
> Thanks,
> - Tong
>
>
> > On Feb 4, 2021, at 1:34 PM, Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
> >
> > Hi
> >
> > Am 04.02.21 um 15:57 schrieb Gerd Hoffmann:
> > > This reverts commit b91907a6241193465ca92e357adf16822242296d.
> >
> > This should be in the correct format, as given by 'dim cite'.
> >
> > dim cite b91907a6241193465ca92e357adf16822242296d
> > b91907a62411 ("drm/qxl: do not run release if qxl failed to init")
> >
> > > Patch is broken, it effectively makes qxl_drm_release() a nop
> > > because on normal driver shutdown qxl_drm_release() is called
> > > *after* drm_dev_unregister().
> > > Cc: Tong Zhang <ztong0001@xxxxxxxxx>
> > > Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> > > ---
> > >   drivers/gpu/drm/qxl/qxl_drv.c | 2 --
> > >   1 file changed, 2 deletions(-)
> > > diff --git a/drivers/gpu/drm/qxl/qxl_drv.c b/drivers/gpu/drm/qxl/qxl_drv.c
> > > index 34c8b25b5780..fb5f6a5e81d7 100644
> > > --- a/drivers/gpu/drm/qxl/qxl_drv.c
> > > +++ b/drivers/gpu/drm/qxl/qxl_drv.c
> > > @@ -144,8 +144,6 @@ static void qxl_drm_release(struct drm_device *dev)
> > >   	 * reodering qxl_modeset_fini() + qxl_device_fini() calls is
> > >   	 * non-trivial though.
> > >   	 */
> > > -	if (!dev->registered)
> > > -		return;
> >
> > I'm not sure what the original problem was, but I'm sure that this isn't the fix for it. If there's a problem with shutdown, the operations rather have to be reordered correctly.
> >
> > With the citation style address:
> >
> > Acked-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
> >
> > >   	qxl_modeset_fini(qdev);
> > >   	qxl_device_fini(qdev);
> > >   }
> >
> > --
> > Thomas Zimmermann
> > Graphics Driver Developer
> > SUSE Software Solutions Germany GmbH
> > Maxfeldstr. 5, 90409 Nürnberg, Germany
> > (HRB 36809, AG Nürnberg)
> > Geschäftsführer: Felix Imendörffer

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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