From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthias Kaehlcke Subject: Re: [PATCH] drm/bridge: dw-hdmi: Refuse DDC/CI transfers on the internal I2C controller Date: Fri, 19 Jul 2019 09:45:45 -0700 Message-ID: <20190719164545.GU250418@google.com> References: <20190718214135.79445-1-mka@chromium.org> <617ef7670a35f0be6beba79ecdaba8be26154868.camel@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from mail-pg1-x543.google.com (mail-pg1-x543.google.com [IPv6:2607:f8b0:4864:20::543]) by gabe.freedesktop.org (Postfix) with ESMTPS id CD81B6E819 for ; Fri, 19 Jul 2019 16:45:49 +0000 (UTC) Received: by mail-pg1-x543.google.com with SMTP id u17so14708859pgi.6 for ; Fri, 19 Jul 2019 09:45:49 -0700 (PDT) Content-Disposition: inline In-Reply-To: <617ef7670a35f0be6beba79ecdaba8be26154868.camel@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Adam Jackson Cc: Jose Abreu , Neil Armstrong , David Airlie , Douglas Anderson , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Laurent Pinchart List-Id: dri-devel@lists.freedesktop.org T24gRnJpLCBKdWwgMTksIDIwMTkgYXQgMTI6MjM6MjZQTSAtMDQwMCwgQWRhbSBKYWNrc29uIHdy b3RlOgo+IE9uIFRodSwgMjAxOS0wNy0xOCBhdCAxNDo0MSAtMDcwMCwgTWF0dGhpYXMgS2FlaGxj a2Ugd3JvdGU6Cj4gCj4gPiBkaWZmIC0tZ2l0IGEvZHJpdmVycy9ncHUvZHJtL2JyaWRnZS9zeW5v cHN5cy9kdy1oZG1pLmMgYi9kcml2ZXJzL2dwdS9kcm0vYnJpZGdlL3N5bm9wc3lzL2R3LWhkbWku Ywo+ID4gaW5kZXggMDQ1YjFiMTNmZDBlLi5lNDk0MDJlYmQ1NmYgMTAwNjQ0Cj4gPiAtLS0gYS9k cml2ZXJzL2dwdS9kcm0vYnJpZGdlL3N5bm9wc3lzL2R3LWhkbWkuYwo+ID4gKysrIGIvZHJpdmVy cy9ncHUvZHJtL2JyaWRnZS9zeW5vcHN5cy9kdy1oZG1pLmMKPiA+IEBAIC0zNSw2ICszNSw3IEBA Cj4gPiAgCj4gPiAgI2luY2x1ZGUgPG1lZGlhL2NlYy1ub3RpZmllci5oPgo+ID4gIAo+ID4gKyNk ZWZpbmUgRERDX0kyQ19BRERSCQkweDM3Cj4gCj4gVGhpcyBjb25mdXNlZCB0aGUgaGVjayBvdXQg b2YgbWUgdG8gcmVhZCwgRERDIGJ5IGRlZmluaXRpb24gaGFwcGVucwo+IG92ZXIgSTJDIGFuZCB0 aGlzIG9uZSBhZGRyZXNzIGlzIGp1c3QgZm9yIGEgc3BlY2lmaWMgc3Vic2V0IG9mIEREQy4KPiBQ ZXJoYXBzIHRoaXMgd291bGQgYmUgY2xlYXJlciBpZiBpdCB3YXMgbmFtZWQgRERDX0NJX0FERFIu CgpJIHdhcyBhbHNvIGEgYml0IGNvbmZ1c2VkIGFib3V0IHRoZSB0ZXJtaW5vbG9neSwgc29tZSBw bGFjZXMgY2FsbCAweDM3CnRoZSBEREMgYWRkcmVzcyBhbmQgMHg1MCB0aGUgRURJRCBhZGRyZXNz LgoKRERDX0NJX0FERFIgc291bmRzIGdvb2QgdG8gbWUsIHRoYW5rcyBmb3IgdGhlIHN1Z2dlc3Rp b24hCgpJJ2xsIHdhaXQgYSBkYXkgb3IgdHdvIGJlZm9yZSByZXNwaW5uaW5nLCBmb3IgaWYgdGhl cmUgYXJlIG1vcmUgY29tbWVudHMuCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fCmRyaS1kZXZlbCBtYWlsaW5nIGxpc3QKZHJpLWRldmVsQGxpc3RzLmZyZWVk ZXNrdG9wLm9yZwpodHRwczovL2xpc3RzLmZyZWVkZXNrdG9wLm9yZy9tYWlsbWFuL2xpc3RpbmZv L2RyaS1kZXZlbA== From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 02D88C7618F for ; 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Fri, 19 Jul 2019 09:45:49 -0700 (PDT) Received: from localhost ([2620:15c:202:1:75a:3f6e:21d:9374]) by smtp.gmail.com with ESMTPSA id 81sm52126164pfx.111.2019.07.19.09.45.48 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 19 Jul 2019 09:45:49 -0700 (PDT) Date: Fri, 19 Jul 2019 09:45:45 -0700 From: Matthias Kaehlcke To: Adam Jackson Cc: Andrzej Hajda , Laurent Pinchart , David Airlie , Daniel Vetter , Jose Abreu , Neil Armstrong , Douglas Anderson , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm/bridge: dw-hdmi: Refuse DDC/CI transfers on the internal I2C controller Message-ID: <20190719164545.GU250418@google.com> References: <20190718214135.79445-1-mka@chromium.org> <617ef7670a35f0be6beba79ecdaba8be26154868.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <617ef7670a35f0be6beba79ecdaba8be26154868.camel@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 19, 2019 at 12:23:26PM -0400, Adam Jackson wrote: > On Thu, 2019-07-18 at 14:41 -0700, Matthias Kaehlcke wrote: > > > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c > > index 045b1b13fd0e..e49402ebd56f 100644 > > --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c > > +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c > > @@ -35,6 +35,7 @@ > > > > #include > > > > +#define DDC_I2C_ADDR 0x37 > > This confused the heck out of me to read, DDC by definition happens > over I2C and this one address is just for a specific subset of DDC. > Perhaps this would be clearer if it was named DDC_CI_ADDR. I was also a bit confused about the terminology, some places call 0x37 the DDC address and 0x50 the EDID address. DDC_CI_ADDR sounds good to me, thanks for the suggestion! I'll wait a day or two before respinning, for if there are more comments.