From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Boris Brezillon <boris.brezillon@collabora.com>
Cc: dri-devel@lists.freedesktop.org,
Mark Rutland <mark.rutland@arm.com>,
Neil Armstrong <narmstrong@baylibre.com>,
Thierry Reding <thierry.reding@gmail.com>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
kernel@collabora.com, Sam Ravnborg <sam@ravnborg.org>,
Nikita Yushchenko <nikita.yoush@cogentembedded.com>,
Andrey Smirnov <andrew.smirnov@gmail.com>,
Kyungmin Park <kyungmin.park@samsung.com>,
Chris Healy <cphealy@gmail.com>,
devicetree@vger.kernel.org, Jonas Karlman <jonas@kwiboo.se>,
Rob Herring <robh+dt@kernel.org>,
Jernej Skrabec <jernej.skrabec@siol.net>,
Seung-Woo Kim <sw0312.kim@samsung.com>,
Andrzej Hajda <a.hajda@samsung.com>
Subject: Re: [PATCH v4 04/11] drm/bridge: Make the bridge chain a double-linked list
Date: Mon, 23 Dec 2019 10:55:16 +0100 [thread overview]
Message-ID: <60f03d50-7c0f-c3d0-920f-0625c08b2171@samsung.com> (raw)
In-Reply-To: <20191216162542.261c821c@collabora.com>
Hi Boris,
On 16.12.2019 16:25, Boris Brezillon wrote:
> On Mon, 16 Dec 2019 16:02:36 +0100
> Marek Szyprowski <m.szyprowski@samsung.com> wrote:
>> Hi Boris,
>>
>> On 16.12.2019 15:55, Boris Brezillon wrote:
>>> On Mon, 16 Dec 2019 14:54:25 +0100
>>> Marek Szyprowski <m.szyprowski@samsung.com> wrote:
>>>> On 03.12.2019 15:15, Boris Brezillon wrote:
>>>>> So that each element in the chain can easily access its predecessor.
>>>>> This will be needed to support bus format negotiation between elements
>>>>> of the bridge chain.
>>>>>
>>>>> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
>>>>> Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
>>>>> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>>>> I've noticed that this patch got merged to linux-next as commit
>>>> 05193dc38197021894b17239fafbd2eb1afe5a45. Sadly it breaks booting of
>>>> Samsung Exynos5250-based Arndale board. Booting stops after following
>>>> messages:
>>>>
>>>> [drm] Exynos DRM: using 14400000.fimd device for DMA mapping operations
>>>> exynos-drm exynos-drm: bound 14400000.fimd (ops fimd_component_ops)
>>>> exynos-drm exynos-drm: bound 14450000.mixer (ops mixer_component_ops)
>>>> exynos-drm exynos-drm: bound 14500000.dsi (ops exynos_dsi_component_ops)
>>>> exynos-drm exynos-drm: bound 14530000.hdmi (ops hdmi_component_ops)
>>>> [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
>>>> [drm] No driver support for vblank timestamp query.
>>>> [drm] Cannot find any crtc or sizes
>>>> [drm] Cannot find any crtc or sizes
>>>> [drm] Initialized exynos 1.1.0 20180330 for exynos-drm on minor 0
>>>>
>>>> I will try to debug this and provide more information soon.
>>>>
>>> Can you try with this diff applied?
>> This patch doesn't change anything.
> Okay. Can you do a list_for_each_entry() on both encoder->bridge_chain
> and dsi->bridge_chain (dump bridge pointers in a pr_info()) before and
> after the list_splice_init() call?
encoder->bridge_chain contains only one element. dsi->drive_chain is empty.
Replacing that list_splice() with INIT_LIST_HEAD(&encoder->bridge_chain)
fixed the boot issue. It looks that this is related with the way the
Exynos DSI handles bridges (in bridge and out brige?). Maybe Andrzej
will give a bit more detailed comment and spread some light on this.
I can send a formal patch fixing this if You want.
>>> --->8---
>>> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
>>> index 3955f84dc893..118ecedc7621 100644
>>> --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
>>> +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
>>> @@ -1523,7 +1523,7 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
>>> if (out_bridge) {
>>> drm_bridge_attach(encoder, out_bridge, NULL);
>>> dsi->out_bridge = out_bridge;
>>> - list_splice(&encoder->bridge_chain, &dsi->bridge_chain);
>>> + list_splice_init(&encoder->bridge_chain, &dsi->bridge_chain);
>>> } else {
>>> int ret = exynos_dsi_create_connector(encoder);
>>>
>>> diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c
>>> index 6c5b80ad6154..e1378d48210f 100644
>>> --- a/drivers/gpu/drm/vc4/vc4_dsi.c
>>> +++ b/drivers/gpu/drm/vc4/vc4_dsi.c
>>> @@ -1613,7 +1613,7 @@ static int vc4_dsi_bind(struct device *dev, struct device *master, void *data)
>>> * from our driver, since we need to sequence them within the
>>> * encoder's enable/disable paths.
>>> */
>>> - list_splice(&dsi->encoder->bridge_chain, &dsi->bridge_chain);
>>> + list_splice_init(&dsi->encoder->bridge_chain, &dsi->bridge_chain);
>>>
>>> if (dsi->port == 0)
>>> vc4_debugfs_add_regset32(drm, "dsi0_regs", &dsi->regset);
>>> @@ -1639,7 +1639,7 @@ static void vc4_dsi_unbind(struct device *dev, struct device *master,
>>> * Restore the bridge_chain so the bridge detach procedure can happen
>>> * normally.
>>> */
>>> - list_splice(&dsi->bridge_chain, &dsi->encoder->bridge_chain);
>>> + list_splice_init(&dsi->bridge_chain, &dsi->encoder->bridge_chain);
>>> vc4_dsi_encoder_destroy(dsi->encoder);
>>>
>>> if (dsi->port == 1)
>>>
>>>
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
next prev parent reply other threads:[~2019-12-23 9:55 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-03 14:15 [PATCH v4 00/11] drm: Add support for bus-format negotiation Boris Brezillon
2019-12-03 14:15 ` [PATCH v4 01/11] drm/bridge: Rename bridge helpers targeting a bridge chain Boris Brezillon
2019-12-03 14:15 ` [PATCH v4 02/11] drm/bridge: Introduce drm_bridge_get_next_bridge() Boris Brezillon
2019-12-03 14:15 ` [PATCH v4 03/11] drm: Stop accessing encoder->bridge directly Boris Brezillon
2019-12-03 14:15 ` [PATCH v4 04/11] drm/bridge: Make the bridge chain a double-linked list Boris Brezillon
2019-12-16 13:54 ` Marek Szyprowski
2019-12-16 14:55 ` Boris Brezillon
2019-12-16 15:02 ` Marek Szyprowski
2019-12-16 15:25 ` Boris Brezillon
2019-12-23 9:55 ` Marek Szyprowski [this message]
2019-12-24 9:16 ` Andrzej Hajda
2019-12-24 9:44 ` Boris Brezillon
2019-12-24 9:49 ` Boris Brezillon
2019-12-24 10:03 ` Boris Brezillon
2019-12-27 10:25 ` Marek Szyprowski
2019-12-27 11:03 ` Marek Szyprowski
2019-12-24 11:31 ` Sam Ravnborg
2019-12-25 1:36 ` Laurent Pinchart
2019-12-27 12:39 ` Boris Brezillon
2019-12-27 9:42 ` Andrzej Hajda
2019-12-27 10:51 ` Laurent Pinchart
2019-12-27 12:21 ` Boris Brezillon
2020-01-01 17:13 ` Laurent Pinchart
2019-12-03 14:15 ` [PATCH v4 05/11] drm/bridge: Add the drm_for_each_bridge_in_chain() helper Boris Brezillon
2019-12-03 14:15 ` [PATCH v4 06/11] drm/bridge: Add the drm_bridge_get_prev_bridge() helper Boris Brezillon
2019-12-03 14:15 ` [PATCH v4 07/11] drm/bridge: Clarify the atomic enable/disable hooks semantics Boris Brezillon
2019-12-03 18:02 ` Laurent Pinchart
2019-12-04 9:00 ` Boris Brezillon
2019-12-03 14:15 ` [PATCH v4 08/11] drm/bridge: Add a drm_bridge_state object Boris Brezillon
2019-12-03 18:17 ` Laurent Pinchart
2019-12-04 9:03 ` Boris Brezillon
2019-12-04 9:12 ` Laurent Pinchart
2019-12-04 9:42 ` Boris Brezillon
2019-12-04 10:38 ` Laurent Pinchart
2019-12-03 14:15 ` [PATCH v4 09/11] drm/bridge: Patch atomic hooks to take a drm_bridge_state Boris Brezillon
2019-12-03 14:15 ` [PATCH v4 10/11] drm/bridge: Add an ->atomic_check() hook Boris Brezillon
2019-12-03 14:15 ` [PATCH v4 11/11] drm/bridge: Add the necessary bits to support bus format negotiation Boris Brezillon
2019-12-03 18:19 ` [PATCH v4 00/11] drm: Add support for bus-format negotiation Laurent Pinchart
2019-12-04 9:09 ` Boris Brezillon
2019-12-04 9:15 ` Laurent Pinchart
2019-12-04 13:43 ` Neil Armstrong
2019-12-09 9:43 ` Boris Brezillon
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