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;

Best regards
Thomas

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.

        qxl_modeset_fini(qdev);
        qxl_device_fini(qdev);

Thanks,
- Tong

On Feb 4, 2021, at 1:34 PM, Thomas Zimmermann <tzimmerm...@suse.de> 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 <ztong0...@gmail.com>
Signed-off-by: Gerd Hoffmann <kra...@redhat.com>
---
  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 <tzimmerm...@suse.de>

        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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