From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: Re: [PATCH v3] drm/bridge/sii902x: Fix EDID readback Date: Thu, 15 Nov 2018 11:16:11 +0100 Message-ID: <20181115111611.783e5c42@bbrezillon> References: <1541505156-8097-1-git-send-email-fabrizio.castro@bp.renesas.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Linus Walleij Cc: Fabrizio Castro , Geert Uytterhoeven , Simon Horman , Wolfram Sang , Dave Airlie , Boris BREZILLON , Chris Paterson , "open list:DRM PANEL DRIVERS" , Biju Das , Linux-Renesas , Mark Brown , Laurent Pinchart , Peter Rosin , linux-i2c@vger.kernel.org List-Id: linux-i2c@vger.kernel.org T24gVGh1LCAxNSBOb3YgMjAxOCAxMToxMzo1MiArMDEwMApMaW51cyBXYWxsZWlqIDxsaW51cy53 YWxsZWlqQGxpbmFyby5vcmc+IHdyb3RlOgoKPiBPbiBUdWUsIE5vdiA2LCAyMDE4IGF0IDEyOjUy IFBNIEZhYnJpemlvIENhc3Rybwo+IDxmYWJyaXppby5jYXN0cm9AYnAucmVuZXNhcy5jb20+IHdy b3RlOgo+IAo+ID4gV2hpbGUgYWRkaW5nIFNpSTkwMjJBIHN1cHBvcnQgdG8gdGhlIGl3ZzIzcyBi b2FyZCwgaXQgY2FtZQo+ID4gdXAgdGhhdCB3aGVuIHRoZSBIRE1JIHRyYW5zbWl0dGVyIGlzIGlu IHBhc3MgdGhyb3VnaCBtb2RlIHRoZQo+ID4gZGV2aWNlIGlzIG5vdCBjb21wbGlhbnQgd2l0aCB0 aGUgSTJDIHNwZWNpZmljYXRpb24gYW55bW9yZSwKPiA+IGFzIGl0IHJlcXVpcmVzIGEgZmFyIGJp Z2dlciB0YnVmLCBkdWUgdG8gYSBkZWxheSB0aGUgSERNSQo+ID4gdHJhbnNtaXR0ZXIgaXMgYWRk aW5nIHdoZW4gcmVsYXlpbmcgdGhlIFNUT1AgY29uZGl0aW9uIG9uIHRoZQo+ID4gbW9uaXRvciBp MmMgc2lkZSBvZiB0aGluZ3MuCj4gPgo+ID4gV2hlbiBub3QgcHJvdmlkaW5nIGFuIGFwcHJvcHJp YXRlIGRlbGF5IGFmdGVyIHRoZSBTVE9QIGNvbmRpdGlvbgo+ID4gdGhlIGkyYyBidXMgd291bGQg Z2V0IHN0dWNrLiBBbHNvLCBhbnkgb3RoZXIgdHJhZmZpYyBvbiB0aGUgYnVzCj4gPiB3aGlsZSB0 YWxraW5nIHRvIHRoZSBtb25pdG9yIG1heSBjYXVzZSB0aGUgdHJhbnNhY3Rpb24gdG8gZmFpbAo+ ID4gb3IgZXZlbiBjYXVzZSBpc3N1ZXMgd2l0aCB0aGUgaTJjIGJ1cyBhcyB3ZWxsLgo+ID4KPiA+ IEkyYy1nYXRlcyBzZWVtZWQgdG8gcmVhY2ggY29uc2VudCBhcyBhIHBvc3NpYmxlIHdheSB0byBh ZGRyZXNzCj4gPiB0aGVzZSBpc3N1ZXMsIGFuZCBhcyBzdWNoIHRoaXMgcGF0Y2ggaXMgaW1wbGVt ZW50aW5nIGEgc29sdXRpb24KPiA+IGJhc2VkIG9uIHRoYXQuIFNpbmNlIG90aGVycyBhcmUgY2xl YXJseSByZWx5aW5nIG9uIHRoZSBjdXJyZW50Cj4gPiBpbXBsZW1lbnRhdGlvbiBvZiB0aGUgZHJp dmVyLCB0aGlzIHBhdGNoIHdvbid0IHJlcXVpcmUgYW55IERUCj4gPiBjaGFuZ2VzLgo+ID4KPiA+ IFNpbmNlIHdlIGRvbid0IHdhbnQgYW55IGludGVyZmVyZW5jZSBkdXJpbmcgdGhlIEREQyBCdXMK PiA+IFJlcXVlc3QvR3JhbnQgcHJvY2VkdXJlIGFuZCB3aGlsZSB0YWxraW5nIHRvIHRoZSBtb25p dG9yLCB3ZQo+ID4gaGF2ZSB0byB1c2UgdGhlIGFkYXB0ZXIgbG9ja2luZyBwcmltaXRpdmVzIHJh dGhlciB0aGFuIHRoZQo+ID4gaTJjLW11eCBsb2NraW5nIHByaW1pdGl2ZXMuCj4gPgo+ID4gU2ln bmVkLW9mZi1ieTogRmFicml6aW8gQ2FzdHJvIDxmYWJyaXppby5jYXN0cm9AYnAucmVuZXNhcy5j b20+Cj4gPgo+ID4gLS0tCj4gPiB2Mi0+djM6Cj4gPiAqIEluY29ycG9yYXRlZCBjb21tZW50cyBm cm9tIEJvcmlzIEJyZXppbGxvbiBhbmQgUGV0ZXIgUm9zaW4gIAo+IAo+IEFja2VkLWJ5OiBMaW51 cyBXYWxsZWlqIDxsaW51cy53YWxsZWlqQGxpbmFyby5vcmc+Cj4gCj4gRG8geW91IG5lZWQgaGVs cCB0byBhcHBseSB0aGlzIHRvIGRybS1taXNjIG9yIGRvIHlvdQo+IGhhdmUgY29tbWl0IGFjY2Vz cz8KCkkgY2FuIGRvIGl0IGlmIG5lZWRlZC4KX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX18KZHJpLWRldmVsIG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMu ZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlzdHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlz dGluZm8vZHJpLWRldmVsCg== From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.bootlin.com ([62.4.15.54]:35350 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728699AbeKOUXZ (ORCPT ); Thu, 15 Nov 2018 15:23:25 -0500 Date: Thu, 15 Nov 2018 11:16:11 +0100 From: Boris Brezillon To: Linus Walleij Cc: Fabrizio Castro , Archit Taneja , Andrzej Hajda , Dave Airlie , Peter Rosin , Wolfram Sang , Mark Brown , Laurent Pinchart , "open list:DRM PANEL DRIVERS" , Simon Horman , Geert Uytterhoeven , Chris Paterson , Biju Das , Linux-Renesas , linux-i2c@vger.kernel.org, Inki Dae , Boris BREZILLON Subject: Re: [PATCH v3] drm/bridge/sii902x: Fix EDID readback Message-ID: <20181115111611.783e5c42@bbrezillon> In-Reply-To: References: <1541505156-8097-1-git-send-email-fabrizio.castro@bp.renesas.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-renesas-soc-owner@vger.kernel.org List-ID: On Thu, 15 Nov 2018 11:13:52 +0100 Linus Walleij wrote: > On Tue, Nov 6, 2018 at 12:52 PM Fabrizio Castro > wrote: > > > While adding SiI9022A support to the iwg23s board, it came > > up that when the HDMI transmitter is in pass through mode the > > device is not compliant with the I2C specification anymore, > > as it requires a far bigger tbuf, due to a delay the HDMI > > transmitter is adding when relaying the STOP condition on the > > monitor i2c side of things. > > > > When not providing an appropriate delay after the STOP condition > > the i2c bus would get stuck. Also, any other traffic on the bus > > while talking to the monitor may cause the transaction to fail > > or even cause issues with the i2c bus as well. > > > > I2c-gates seemed to reach consent as a possible way to address > > these issues, and as such this patch is implementing a solution > > based on that. Since others are clearly relying on the current > > implementation of the driver, this patch won't require any DT > > changes. > > > > Since we don't want any interference during the DDC Bus > > Request/Grant procedure and while talking to the monitor, we > > have to use the adapter locking primitives rather than the > > i2c-mux locking primitives. > > > > Signed-off-by: Fabrizio Castro > > > > --- > > v2->v3: > > * Incorporated comments from Boris Brezillon and Peter Rosin > > Acked-by: Linus Walleij > > Do you need help to apply this to drm-misc or do you > have commit access? I can do it if needed.