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author | Boris Brezillon <boris.brezillon@collabora.com> | 2019-12-27 17:41:23 +0300 |
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committer | Boris Brezillon <boris.brezillon@collabora.com> | 2020-01-08 11:09:48 +0300 |
commit | 033bfe7538a1523f36dd434eaff7c754a555c458 (patch) | |
tree | 42b06f6ebca85cd69df996b5dba543815f4b11b4 /drivers/gpu/drm/vc4 | |
parent | 2ec1431ffac9f891a11ac955a9ee914e0547215e (diff) | |
download | linux-033bfe7538a1523f36dd434eaff7c754a555c458.tar.xz |
drm/vc4: dsi: Fix bridge chain handling
Commit 05193dc38197 ("drm/bridge: Make the bridge chain a double-linked
list") patched the bridge chain logic to use a double-linked list instead
of a single-linked list. This change induced changes to the VC4 driver
which was manually resetting the encoder->bridge element to NULL to
control the enable/disable sequence of the bridge chain. During this
conversion, 2 bugs were introduced:
1/ list_splice() was used to move chain elements to our own internal
chain, but list_splice() does not reset the source list to an empty
state, leading to unexpected bridge hook calls when
drm_bridge_chain_xxx() helpers were called by the core. Replacing
those list_splice() calls by list_splice_init() ones fixes this
problem.
2/ drm_bridge_chain_xxx() helpers operate on the
bridge->encoder->bridge_chain list, which is now empty. When the
helper uses list_for_each_entry_reverse() we end up with no operation
done which is not what we want. But that's even worse when the helper
uses list_for_each_entry_from(), because in that case we end up in
an infinite loop searching for the list head element which is no
longer encoder->bridge_chain but vc4_dsi->bridge_chain. To address
that problem we stop using the bridge chain helpers and call the
hooks directly.
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Eric Anholt <eric@anholt.net>
Fixes: 05193dc38197 ("drm/bridge: Make the bridge chain a double-linked list")
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Acked-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20191227144124.210294-2-boris.brezillon@collabora.com
Diffstat (limited to 'drivers/gpu/drm/vc4')
-rw-r--r-- | drivers/gpu/drm/vc4/vc4_dsi.c | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c index 6c5b80ad6154..fd8a2eb60505 100644 --- a/drivers/gpu/drm/vc4/vc4_dsi.c +++ b/drivers/gpu/drm/vc4/vc4_dsi.c @@ -753,10 +753,19 @@ static void vc4_dsi_encoder_disable(struct drm_encoder *encoder) struct vc4_dsi_encoder *vc4_encoder = to_vc4_dsi_encoder(encoder); struct vc4_dsi *dsi = vc4_encoder->dsi; struct device *dev = &dsi->pdev->dev; + struct drm_bridge *iter; + + list_for_each_entry_reverse(iter, &dsi->bridge_chain, chain_node) { + if (iter->funcs->disable) + iter->funcs->disable(iter); + } - drm_bridge_chain_disable(dsi->bridge); vc4_dsi_ulps(dsi, true); - drm_bridge_chain_post_disable(dsi->bridge); + + list_for_each_entry_from(iter, &dsi->bridge_chain, chain_node) { + if (iter->funcs->post_disable) + iter->funcs->post_disable(iter); + } clk_disable_unprepare(dsi->pll_phy_clock); clk_disable_unprepare(dsi->escape_clock); @@ -824,6 +833,7 @@ static void vc4_dsi_encoder_enable(struct drm_encoder *encoder) struct vc4_dsi *dsi = vc4_encoder->dsi; struct device *dev = &dsi->pdev->dev; bool debug_dump_regs = false; + struct drm_bridge *iter; unsigned long hs_clock; u32 ui_ns; /* Minimum LP state duration in escape clock cycles. */ @@ -1056,7 +1066,10 @@ static void vc4_dsi_encoder_enable(struct drm_encoder *encoder) vc4_dsi_ulps(dsi, false); - drm_bridge_chain_pre_enable(dsi->bridge); + list_for_each_entry_reverse(iter, &dsi->bridge_chain, chain_node) { + if (iter->funcs->pre_enable) + iter->funcs->pre_enable(iter); + } if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO) { DSI_PORT_WRITE(DISP0_CTRL, @@ -1073,7 +1086,10 @@ static void vc4_dsi_encoder_enable(struct drm_encoder *encoder) DSI_DISP0_ENABLE); } - drm_bridge_chain_enable(dsi->bridge); + list_for_each_entry(iter, &dsi->bridge_chain, chain_node) { + if (iter->funcs->enable) + iter->funcs->enable(iter); + } if (debug_dump_regs) { struct drm_printer p = drm_info_printer(&dsi->pdev->dev); @@ -1613,7 +1629,7 @@ 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 +1655,7 @@ 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) |