From: Heiko Stuebner <heiko@sntech.de>
To: Damian Kos <dkos@cadence.com>
Cc: David Airlie <airlied@linux.ie>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
linux-rockchip@lists.infradead.org,
Chris Zhong <zyw@rock-chips.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] drm/rockchip: fix for mailbox read size
Date: Mon, 19 Nov 2018 15:18:33 +0100 [thread overview]
Message-ID: <7088529.fTnRXqZmiP@phil> (raw)
In-Reply-To: <1541518625-25984-1-git-send-email-dkos@cadence.com>
Am Dienstag, 6. November 2018, 16:37:05 CET schrieb Damian Kos:
> Some of the functions (like cdn_dp_dpcd_read, cdn_dp_get_edid_block)
> allow to read 64KiB, but the cdn_dp_mailbox_read_receive, that is
> used by them, can read only up to 255 bytes at once. Normally, it's
> not a big issue as DPCD or EDID reads won't (hopefully) exceed that
> value.
> The real issue here is the revocation list read during the HDCP
> authentication process. (problematic use case:
> https://chromium.googlesource.com/chromiumos/third_party/kernel/+/chromeos-4.4/drivers/gpu/drm/rockchip/cdn-dp-reg.c#1152)
> The list can reach 127*5+4 bytes (num devs * 5 bytes per ID/Bksv +
> 4 bytes of an additional info).
> In other words - CTSes with HDCP Repeater won't pass without this
> fix. Oh, and the driver will most likely stop working (best case
> scenario).
>
> Signed-off-by: Damian Kos <dkos@cadence.com>
applied to drm-misc-next
Thanks
Heiko
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WARNING: multiple messages have this Message-ID (diff)
From: heiko@sntech.de (Heiko Stuebner)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] drm/rockchip: fix for mailbox read size
Date: Mon, 19 Nov 2018 15:18:33 +0100 [thread overview]
Message-ID: <7088529.fTnRXqZmiP@phil> (raw)
In-Reply-To: <1541518625-25984-1-git-send-email-dkos@cadence.com>
Am Dienstag, 6. November 2018, 16:37:05 CET schrieb Damian Kos:
> Some of the functions (like cdn_dp_dpcd_read, cdn_dp_get_edid_block)
> allow to read 64KiB, but the cdn_dp_mailbox_read_receive, that is
> used by them, can read only up to 255 bytes at once. Normally, it's
> not a big issue as DPCD or EDID reads won't (hopefully) exceed that
> value.
> The real issue here is the revocation list read during the HDCP
> authentication process. (problematic use case:
> https://chromium.googlesource.com/chromiumos/third_party/kernel/+/chromeos-4.4/drivers/gpu/drm/rockchip/cdn-dp-reg.c#1152)
> The list can reach 127*5+4 bytes (num devs * 5 bytes per ID/Bksv +
> 4 bytes of an additional info).
> In other words - CTSes with HDCP Repeater won't pass without this
> fix. Oh, and the driver will most likely stop working (best case
> scenario).
>
> Signed-off-by: Damian Kos <dkos@cadence.com>
applied to drm-misc-next
Thanks
Heiko
WARNING: multiple messages have this Message-ID (diff)
From: Heiko Stuebner <heiko@sntech.de>
To: Damian Kos <dkos@cadence.com>
Cc: Chris Zhong <zyw@rock-chips.com>,
Sandy Huang <hjc@rock-chips.com>, David Airlie <airlied@linux.ie>,
dri-devel@lists.freedesktop.org,
linux-arm-kernel@lists.infradead.org,
linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drm/rockchip: fix for mailbox read size
Date: Mon, 19 Nov 2018 15:18:33 +0100 [thread overview]
Message-ID: <7088529.fTnRXqZmiP@phil> (raw)
In-Reply-To: <1541518625-25984-1-git-send-email-dkos@cadence.com>
Am Dienstag, 6. November 2018, 16:37:05 CET schrieb Damian Kos:
> Some of the functions (like cdn_dp_dpcd_read, cdn_dp_get_edid_block)
> allow to read 64KiB, but the cdn_dp_mailbox_read_receive, that is
> used by them, can read only up to 255 bytes at once. Normally, it's
> not a big issue as DPCD or EDID reads won't (hopefully) exceed that
> value.
> The real issue here is the revocation list read during the HDCP
> authentication process. (problematic use case:
> https://chromium.googlesource.com/chromiumos/third_party/kernel/+/chromeos-4.4/drivers/gpu/drm/rockchip/cdn-dp-reg.c#1152)
> The list can reach 127*5+4 bytes (num devs * 5 bytes per ID/Bksv +
> 4 bytes of an additional info).
> In other words - CTSes with HDCP Repeater won't pass without this
> fix. Oh, and the driver will most likely stop working (best case
> scenario).
>
> Signed-off-by: Damian Kos <dkos@cadence.com>
applied to drm-misc-next
Thanks
Heiko
next prev parent reply other threads:[~2018-11-19 14:18 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-06 15:37 [PATCH] drm/rockchip: fix for mailbox read size Damian Kos
2018-11-06 15:37 ` Damian Kos
2018-11-19 14:18 ` Heiko Stuebner [this message]
2018-11-19 14:18 ` Heiko Stuebner
2018-11-19 14:18 ` Heiko Stuebner
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