Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1456495
| Path | csiph.com!news.mixmin.net!aioe.org!bofh.it!news.nic.it!robomod |
|---|---|
| From | Russell King - ARM Linux <linux@armlinux.org.uk> |
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 2/3 v3] drm: bridge/dw-hdmi: Enable ISCR1, ISCR2 and ACP packets |
| Date | Thu, 04 Aug 2016 17:40:02 +0200 |
| Message-ID | <s2sUy-2Lw-29@gated-at.bofh.it> (permalink) |
| References | <s2onT-7Kf-7@gated-at.bofh.it> <s2onT-7Kf-5@gated-at.bofh.it> |
| Dkim-Signature | v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2014; h=Sender:In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date; bh=DlXlvPbm/7AOEBGggMR9g35uK1/AngJOHgjjlykW/b4=; b=ajcQUfm2P6drONnVzM524Xg1tN8d3+oSN2Go7WNOa8ehJxQuhpWCnl0vUL/wqRhp+1jJsLFcI4sLUn9kIJfAQz2mO4QJBLlARNkmT4h791JcNiKWjZ0ta6uItCxkWiGzzuTT7Ted0pjXA3dpj77KbLz5tPHgB91w3zXEu4ItTDk=; |
| MIME-Version | 1.0 |
| Content-Type | text/plain; charset=us-ascii |
| Content-Disposition | inline |
| User-Agent | Mutt/1.5.23 (2014-03-12) |
| Sender | robomod@news.nic.it |
| List-ID | <linux-kernel.vger.kernel.org> |
| X-Mailing-List | linux-kernel@vger.kernel.org |
| Approved | robomod@news.nic.it |
| Lines | 51 |
| Organization | linux.* mail to news gateway |
| X-Original-Cc | dri-devel@lists.freedesktop.org, Carlos Palminha <CARLOS.PALMINHA@synopsys.com>, Archit Taneja <architt@codeaurora.org>, David Airlie <airlied@linux.ie>, Fabio Estevam <fabio.estevam@freescale.com>, Daniel Vetter <daniel.vetter@ffwll.ch>, Takashi Iwai <tiwai@suse.de>, Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>, Thierry Reding <treding@nvidia.com>, linux-kernel@vger.kernel.org |
| X-Original-Date | Thu, 4 Aug 2016 16:32:07 +0100 |
| X-Original-Message-ID | <20160804153206.GX1041@n2100.armlinux.org.uk> |
| X-Original-References | <cover.1470306826.git.joabreu@synopsys.com> <24dfd753e075c70d7b9b429b2d5f42ce9b1562a1.1470306826.git.joabreu@synopsys.com> |
| X-Original-Sender | linux-kernel-owner@vger.kernel.org |
| Xref | csiph.com linux.kernel:1456495 |
Show key headers only | View raw
On Thu, Aug 04, 2016 at 11:44:50AM +0100, Jose Abreu wrote:
> Currently ISCR and ACP packets are not being sent causing
> HDMI compliance tests like CTS 7-19 HDMI 1.4b to fail.
Hmm. Reading the HDMI specifications (v1.3, being the publically
available one), the specification does _not_ say that a source _must_
transmit ISRC and ACP packets if Supports_AI is set.
What it does say is that:
* a sink shall set Supports_AI if it supports at least one function
which uses ISRC or ACP packets, and it shall accept such packets.
* a source shall not transmit ISRC or ACP packets to a sink that
has Supports_AI=0.
I don't see anything that mandates the transmission of ISRC and ACP
packets when Supports_AI is set.
Moreover, transmission of wrong ISRC information probably goes against
the HDMI spec section 8.8, which requires specific ISRC status values
in HB1 - I don't see how that _could_ be handled, as the kernel has no
knowledge about the EAN of the audio content being played, nor when a
track starts or finishes.
Please clarify.
> + /* Set ISCR1, ISCR2, and ACP packets to automatic scheduling */
> + if (hdmi->sink_supports_ai) {
> + dev_dbg(hdmi->dev, "sink supports AI packets\n");
> + hdmi_writeb(hdmi, 0x06, HDMI_FC_ISCR1_0);
> + hdmi_writeb(hdmi, 0x03, HDMI_FC_DATAUTO0);
> + hdmi_writeb(hdmi, 0x01, HDMI_FC_DATAUTO1);
> + hdmi_writeb(hdmi, 0x11, HDMI_FC_DATAUTO2);
So what data gets sent in these packets - I guess whatever random data
happens to be in the HDMI_FC_ACP* and HDMI_FC_ISCR1_* registers at the
time the sending is enabled. I don't think that's particularly a good
idea.
> @@ -1474,8 +1490,13 @@ static int dw_hdmi_connector_get_modes(struct drm_connector *connector)
> /* Store the ELD */
> drm_edid_to_eld(connector, edid);
> kfree(edid);
> +
> + hdmi->sink_supports_ai = connector->eld[5] & (0x1 << 1);
We have a definition for this bit - DRM_ELD_SUPPORTS_AI.
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH 2/3 v3] drm: bridge/dw-hdmi: Enable ISCR1, ISCR2 and ACP packets Jose Abreu <Jose.Abreu@synopsys.com> - 2016-08-04 12:50 +0200
Re: [PATCH 2/3 v3] drm: bridge/dw-hdmi: Enable ISCR1, ISCR2 and ACP packets Russell King - ARM Linux <linux@armlinux.org.uk> - 2016-08-04 17:40 +0200
Re: [PATCH 2/3 v3] drm: bridge/dw-hdmi: Enable ISCR1, ISCR2 and ACP packets Jose Abreu <Jose.Abreu@synopsys.com> - 2016-08-04 18:20 +0200
csiph-web