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To:     "Chenfeng \(puck\)" <puck.chen@hisilicon.com>,
        "Liuxinliang \(Matthew Liu\)" <z.liuxinliang@hisilicon.com>,
        "airlied@linux.ie" <airlied@linux.ie>,
        "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>,
        "zourongrong@gmail.com" <zourongrong@gmail.com>,
        John Garry <john.garry@huawei.com>
From:   Chris Wilson <chris@chris-wilson.co.uk>
In-Reply-To: <e8f99d84-422f-f79f-f207-e9658b190800@huawei.com>
Cc:     Linuxarm <linuxarm@huawei.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        daniel.vetter@ffwll.ch
References: <d390c2df-64f6-484e-e48f-953e88cc4501@huawei.com>
 <40ead141-6d9d-31bf-4b62-639b31db9793@huawei.com>
 <5BA48650.7050505@hisilicon.com>
 <e8f99d84-422f-f79f-f207-e9658b190800@huawei.com>
Message-ID: <153754012047.21139.481244931312769112@skylake-alporthouse-com>
User-Agent: alot/0.6
Subject: Re: Bug report: HiBMC crash
Date:   Fri, 21 Sep 2018 15:28:40 +0100
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Quoting John Garry (2018-09-21 09:11:19)
> On 21/09/2018 06:49, Liuxinliang (Matthew Liu) wrote:
> > Hi John,
> > Thank you for reporting bug.
> > I am now using 4.18.7. I haven't found this issue yet.
> > I will try linux-next and figure out what's wrong with it.
> >
> > Thanks,
> > Xinliang
> >
> >
> 
> As mentioned in internal mail, the issue may be that the surface 
> depth/bpp we were using the in the driver was previously invalid, but 
> code has since been added in v4.19 to reject this. Specifically it looks 
> like this patch:
> 
> commit 70109354fed232dfce8fb2c7cadf635acbe03e19
> Author: Chris Wilson <chris@chris-wilson.co.uk>
> Date:   Wed Sep 5 16:31:16 2018 +0100
> 
>      drm: Reject unknown legacy bpp and depth for drm_mode_addfb ioctl


diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_fbdev.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_fbdev.c
index b92595c477ef..f3e7f41e6781 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_fbdev.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_fbdev.c
@@ -71,7 +71,6 @@ static int hibmc_drm_fb_create(struct drm_fb_helper *helper,
        DRM_DEBUG_DRIVER("surface width(%d), height(%d) and bpp(%d)\n",
                         sizes->surface_width, sizes->surface_height,
                         sizes->surface_bpp);
-       sizes->surface_depth = 32;

        bytes_per_pixel = DIV_ROUND_UP(sizes->surface_bpp, 8);

@@ -192,7 +191,6 @@ int hibmc_fbdev_init(struct hibmc_drm_private *priv)
                return -ENOMEM;
        }

-       priv->fbdev = hifbdev;
        drm_fb_helper_prepare(priv->dev, &hifbdev->helper,
                              &hibmc_fbdev_helper_funcs);

@@ -246,6 +244,7 @@ int hibmc_fbdev_init(struct hibmc_drm_private *priv)
                         fix->ypanstep, fix->ywrapstep, fix->line_length,
                         fix->accel, fix->capabilities);

+       priv->fbdev = hifbdev;
        return 0;

 fini:

Apply chunks 2&3 first to confirm they fix the GPF.
-Chris