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[85.223.141.74]) by smtp.gmail.com with ESMTPSA id b69sm3909428lfl.28.2018.12.19.06.10.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 19 Dec 2018 06:10:17 -0800 (PST) Subject: Re: [PATCH] drm/bochs: add edid present check To: Gerd Hoffmann , dri-devel@lists.freedesktop.org Cc: David Airlie , open list , "open list:DRM DRIVER FOR BOCHS VIRTUAL GPU" References: <20181218073339.12160-1-kraxel@redhat.com> From: Oleksandr Andrushchenko Message-ID: <93d72578-9567-9694-dbc7-62618b217f8f@gmail.com> Date: Wed, 19 Dec 2018 16:10:11 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181218073339.12160-1-kraxel@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Gerd! On 12/18/18 9:33 AM, Gerd Hoffmann wrote: > Check first two header bytes before trying to read the edid blob, > to avoid the log being spammed in case qemu has no edid support (old > qemu or edid turned off). > > Fixes: 01f23459cf drm/bochs: add edid support. > Signed-off-by: Gerd Hoffmann > --- > drivers/gpu/drm/bochs/bochs_hw.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/gpu/drm/bochs/bochs_hw.c b/drivers/gpu/drm/bochs/bochs_hw.c > index c90a0d492f..f91e049625 100644 > --- a/drivers/gpu/drm/bochs/bochs_hw.c > +++ b/drivers/gpu/drm/bochs/bochs_hw.c > @@ -89,6 +89,10 @@ int bochs_hw_load_edid(struct bochs_device *bochs) > if (!bochs->mmio) > return -1; > You could probably have a comment here explaining the magic below (just like in the commit message to ease the task of understanding while reading the code why 2 of 8 bytes of the EDID header is checked and why it is all needed). Of course one can use git blame... Up to you > + if (readb(bochs->mmio + 0) != 0x00 || > + readb(bochs->mmio + 1) != 0xff) bochs->mmio is defined as "void __iomem   *mmio;". Can we please avoid void pointer arithmetic here? > + return -1; > + > kfree(bochs->edid); > bochs->edid = drm_do_get_edid(&bochs->connector, > bochs_get_edid_block, bochs); With the above fixed: Reviewed-by: Oleksandr Andrushchenko