This is a note to let you know that I've just added the patch titled
drm/i915/vbt: ignore extraneous child devices for a port
to the 4.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-i915-vbt-ignore-extraneous-child-devices-for-a-port.patch
and it can be found in the queue-4.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7c648bde211baeda7a029bd6be4957e8be48d8c9 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula@xxxxxxxxx>
Date: Fri, 11 Aug 2017 14:39:07 +0300
Subject: drm/i915/vbt: ignore extraneous child devices for a port
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From: Jani Nikula <jani.nikula@xxxxxxxxx>
commit 7c648bde211baeda7a029bd6be4957e8be48d8c9 upstream.
Ever since we've parsed VBT child devices, starting from 6acab15a7b0d
("drm/i915: use the HDMI DDI buffer translations from VBT"), we've
ignored the child device information if more than one child device
references the same port. The rationale for this seems lost in time.
Since commit 311a20949f04 ("drm/i915: don't init DP or HDMI when not
supported by DDI port") we started using this information more to skip
HDMI/DP init if the port wasn't there per VBT child devices. However, at
the same time it added port defaults without further explanation.
Thus, if the child device info was skipped due to multiple child devices
referencing the same port, the device info would be retrieved from the
somewhat arbitrary defaults.
Finally, when commit bb1d132935c2 ("drm/i915/vbt: split out defaults
that are set when there is no VBT") stopped initializing the defaults
whenever VBT is present, thus trusting the VBT more, we stopped
initializing ports which were referenced by more than one child device.
Apparently at least Asus UX305UA, UX305U, and UX306U laptops have VBT
child device blocks which cause this behaviour. Arguably they were
shipped with a broken VBT.
Relax the rules for multiple references to the same port, and use the
first child device info to reference a port. Retain the logic to debug
log about this, though.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101745
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=196233
Fixes: bb1d132935c2 ("drm/i915/vbt: split out defaults that are set when there is no VBT")
Tested-by: Oliver Weißbarth <mail@xxxxxxxxxxxxxx>
Reported-by: Oliver Weißbarth <mail@xxxxxxxxxxxxxx>
Reported-by: Didier G <didierg-divers@xxxxxxxxx>
Reported-by: Giles Anderson <agander@xxxxxxxxx>
Cc: Manasi Navare <manasi.d.navare@xxxxxxxxx>
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20170811113907.6716-1-jani.nikula@xxxxxxxxx
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
(cherry picked from commit b5273d72750555a673040070bfb23c454a7cd3ef)
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_bios.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -1120,8 +1120,8 @@ static void parse_ddi_port(struct drm_i9
bool is_dvi, is_hdmi, is_dp, is_edp, is_crt;
uint8_t aux_channel, ddc_pin;
/* Each DDI port can have more than one value on the "DVO Port" field,
- * so look for all the possible values for each port and abort if more
- * than one is found. */
+ * so look for all the possible values for each port.
+ */
int dvo_ports[][3] = {
{DVO_PORT_HDMIA, DVO_PORT_DPA, -1},
{DVO_PORT_HDMIB, DVO_PORT_DPB, -1},
@@ -1130,7 +1130,10 @@ static void parse_ddi_port(struct drm_i9
{DVO_PORT_CRT, DVO_PORT_HDMIE, DVO_PORT_DPE},
};
- /* Find the child device to use, abort if more than one found. */
+ /*
+ * Find the first child device to reference the port, report if more
+ * than one found.
+ */
for (i = 0; i < dev_priv->vbt.child_dev_num; i++) {
it = dev_priv->vbt.child_dev + i;
@@ -1140,11 +1143,11 @@ static void parse_ddi_port(struct drm_i9
if (it->common.dvo_port == dvo_ports[port][j]) {
if (child) {
- DRM_DEBUG_KMS("More than one child device for port %c in VBT.\n",
+ DRM_DEBUG_KMS("More than one child device for port %c in VBT, using the first.\n",
port_name(port));
- return;
+ } else {
+ child = it;
}
- child = it;
}
}
}
Patches currently in stable-queue which might be from jani.nikula@xxxxxxxxx are
queue-4.12/drm-i915-vbt-ignore-extraneous-child-devices-for-a-port.patch