Commit ae71ab585c ("drm/vc4: hdmi: Enforce the minimum rate at
runtime_resume") reintroduced the call to clk_set_min_rate in an attempt
to fix the boot without a monitor connected on the RaspberryPi3.
However, that introduced a regression breaking the display output
entirely (black screen but no vblank timeout) on the Pi4.
This is due to the fact that we now have in a typical modeset at boot,
in vc4_hdmi_encoder_pre_crtc_configure(), we have a first call to
clk_set_min_rate() asking for the minimum rate of the HSM clock for our
given resolution, and then a call to pm_runtime_resume_and_get(). We
will thus execute vc4_hdmi_runtime_resume() which, since the commit
mentioned above, will call clk_set_min_rate() a second time with the
absolute minimum rate we want to enforce on the HSM clock.
We're thus effectively erasing the minimum mandated by the mode we're
trying to set. The fact that only the Pi4 is affected is due to the fact
that it uses a different clock driver that tries to minimize the HSM
clock at all time. It will thus lower the HSM clock rate to 120MHz on
the second clk_set_min_rate() call.
The Pi3 doesn't use the same driver and will not change the frequency on
the second clk_set_min_rate() call since it's still within the new
boundaries and it doesn't have the code to minimize the clock rate as
needed. So even though the boundaries are still off, the clock rate is
still the right one for our given mode, so everything works.
There is a lot of moving parts, so I couldn't find any obvious
solution:
- Reverting the original is not an option, as that would break the Pi3
again.
- We can't move the clk_set_min_rate() call in _pre_crtc_configure()
since because, on the Pi3, the HSM clock has the CLK_SET_RATE_GATE
flag which prevents the clock rate from being changed after it's
been enabled. Our calls to clk_set_min_rate() can change it, so they
need to be done before clk_prepare_enable().
- We can't remove the call to clk_prepare_enable() from the
runtime_resume hook to put it into _pre_crtc_configure() either,
since we need that clock to be enabled to access the registers, and
we can't count on the fact that the display will be active in all
situations (doing any CEC operation, or listing the modes while
inactive are valid for example()).
- We can't drop the call to clk_set_min_rate() in
_pre_crtc_configure() since we would need to still enforce the
minimum rate for a given resolution, and runtime_resume doesn't have
access to the current mode, if there's any.
- We can't copy the TMDS character rate into vc4_hdmi and reuse it
since, because it's part of the KMS atomic state, it needs to be
protected by a mutex. Unfortunately, some functions (CEC operations,
mostly) can be reentrant (through the CEC framework) and still need
a pm_runtime_get.
However, we can work around this issue by leveraging the fact that the
clk_set_min_rate() calls set boundaries for its given struct clk, and
that each different clk_get() call will return a different instance of
struct clk. The clock framework will then aggregate the boundaries for
each struct clk instances linked to a given clock, plus its hardware
boundaries, and will use that.
We can thus get an extra HSM clock user for runtime_pm use only, and use
our different clock instances depending on the context: runtime_pm will
use its own to set the absolute minimum clock setup so that we never
lock the CPU waiting for a register access, and the modeset part will
set its requirement for the current resolution. And we let the CCF do
the coordination.
It's not an ideal solution, but it's fairly unintrusive and doesn't
really change any part of the logic so it looks like a rather safe fix.
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2136234
Fixes: ae71ab585c ("drm/vc4: hdmi: Enforce the minimum rate at runtime_resume")
Reported-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Link: https://lore.kernel.org/r/20221021131339.2203291-1-maxime@cerno.tech
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
In order to support higher HDMI frequencies, users have to set the
hdmi_enable_4kp60 parameter in their config.txt file.
This will have the side-effect of raising the maximum of the core clock,
tied to the HVS, and managed by the HVS driver.
However, we are querying this in the HDMI driver by poking into the HVS
structure to get our struct clk handle.
Let's make this part of the HVS bind implementation to have all the core
clock related setup in the same place.
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://lore.kernel.org/r/20220815-rpi-fix-4k-60-v5-5-fe9e7ac8b111@cerno.tech
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
We recently introduced a new mutex to protect concurrent execution of
ALSA and KMS hooks, and the concurrent access to some of vc4_hdmi
fields.
However, using it in the detect hook was creating a reentrency issue
with CEC code. Indeed, calling cec_s_phys_addr_from_edid from detect
might call the CEC adap_enable hook with the lock held, eventually
resulting in a deadlock.
Since we didn't really need to protect anything at the moment in the CEC
code, the decision was made to ignore the mutex in those CEC hooks,
working around the issue.
However, we can have the same thing happening if we end up triggering a
mode set from the detect callback, for example using
drm_atomic_helper_connector_hdmi_reset_link().
Since we don't really need to protect anything in detect either, let's
just drop the lock in detect, and add it again in CEC.
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220829134731.213478-4-maxime@cerno.tech
The current code to build the registers set later exposed in debugfs for
the HDMI controller relies on traditional allocations, that are later
free'd as part of the driver unbind hook.
Since krealloc doesn't have a DRM-managed equivalent, let's add an action
to free the buffer later on.
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220711173939.1132294-45-maxime@cerno.tech
The current HDMI driver, in vc4_hdmi_audio_can_stream() checks whether
the display output is enabled.
This has been there in one form or the other since the introduction of
the audio support in the VC4 HDMI driver in commit bb7d785688
("drm/vc4: Add HDMI audio support"), but no justification for this check
is in the commit message, or in the discussions around the patches.
One can only assume this was done to prevent a user from playing audio
on the ALSA soundcard when the monitor doesn't support it.
However, this is causing some issues. Indeed, Kodi, for example, was
hitting some errors if it was streaming audio during a modeset. With the
theory above, it does make sense, but the display and audio threads are
typically completely different processes with no opportunity to
synchronise which makes it hard to workaround.
Removing that check also doesn't seem to cause any trouble, so let's
just remove it.
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Link: https://lore.kernel.org/r/20220613144800.326124-25-maxime@cerno.tech
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Once EDID is parsed, the monitor HDMI support information is cached in
drm_display_info.is_hdmi by drm_parse_hdmi_vsdb_video().
This driver calls drm_detect_hdmi_monitor() to receive the same
information and stores its own cached value in
vc4_hdmi_encoder.hdmi_monitor, which is less efficient.
Avoid calling drm_detect_hdmi_monitor() and use drm_display_info.is_hdmi
instead. This also allows to remove vc4_hdmi_encoder.hdmi_monitor.
drm_detect_hdmi_monitor() is called in vc4_hdmi_connector_detect() and
vc4_hdmi_connector_get_modes(). In both cases it is safe to rely on
drm_display_info.is_hdmi as shown by ftrace:
$ sudo trace-cmd record -p function_graph -l "vc4_hdmi_*" -l "drm_*"
vc4_hdmi_connector_detect:
vc4_hdmi_connector_detect() {
drm_get_edid() {
drm_connector_update_edid_property() {
drm_add_display_info() {
drm_reset_display_info();
drm_for_each_detailed_block.part.0();
drm_parse_cea_ext() {
drm_find_cea_extension();
drm_parse_hdmi_vsdb_video();
/* drm_display_info.is_hdmi is cached here */
}
}
}
}
/* drm_display_info.is_hdmi is used here */
}
vc4_hdmi_connector_get_modes:
vc4_hdmi_connector_get_modes() {
drm_get_edid() {
drm_connector_update_edid_property() {
drm_add_display_info() {
drm_reset_display_info();
drm_for_each_detailed_block.part.0();
drm_parse_cea_ext() {
drm_find_cea_extension();
drm_parse_hdmi_vsdb_video();
/* drm_display_info.is_hdmi is cached here */
}
}
}
}
/* drm_display_info.is_hdmi is used here */
drm_connector_update_edid_property();
}
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220420114500.187664-2-jose.exposito89@gmail.com
Currently we take the max_bpc property as the bpc value and do not try
anything else.
However, what the other drivers seem to be doing is that they would try
with the highest bpc allowed by the max_bpc property and the hardware
capabilities, test if it results in an acceptable configuration, and if
not decrease the bpc and try again.
Let's use the same logic.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220222164042.403112-7-maxime@cerno.tech
The CSC callbacks takes a boolean as an argument to tell whether we're
using the full range or limited range RGB.
However, with the upcoming YUV support, the logic will be a bit more
complex. In order to address this, let's make the callbacks take the
entire mode, and call our new helper to tell whether the full or limited
range RGB should be used.
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220120151625.594595-7-maxime@cerno.tech
We currently rely on two functions, vc4_hdmi_supports_scrambling() and
vc4_hdmi_mode_needs_scrambling() to determine if we should enable and
disable the scrambler for any given mode.
Since we might need to disable the controller at boot, we also always
run vc4_hdmi_disable_scrambling() and thus call those functions without
a mode yet, which in turns need to make some special casing in order for
it to work.
Instead of duplicating the check for whether or not we need to take care
of the scrambler in both vc4_hdmi_enable_scrambling() and
vc4_hdmi_disable_scrambling(), we can do that check only when we enable
it and store whether or not it's been enabled in our private structure.
We also need to initialize that flag at true to make sure we disable the
scrambler at boot since we can't really know its state yet.
This allows to simplify a bit that part of the driver, and removes one
user of our copy of the CRTC adjusted mode outside of KMS (since
vc4_hdmi_disable_scrambling() might be called from the hotplug interrupt
handler).
It also removes our last user of the legacy encoder->crtc pointer.
Link: https://lore.kernel.org/r/20211025141113.702757-10-maxime@cerno.tech
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
We currently poke at encoder->crtc in the ALSA code path to determine
whether the HDMI output is enabled or not, and thus whether we should
allow the audio output.
However, that pointer is deprecated and shouldn't really be used by
atomic drivers anymore. Since we have the infrastructure in place now,
let's just create a flag that we toggle to report whether the controller
is currently enabled and use that instead of encoder->crtc in ALSA.
Link: https://lore.kernel.org/r/20211025141113.702757-9-maxime@cerno.tech
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Accessing the crtc->state pointer from outside the modesetting context
is not allowed. We thus need to copy whatever we need from the KMS state
to our structure in order to access it.
However, in the vc4 HDMI driver we do use that pointer in the ALSA code
path, and potentially in the hotplug interrupt handler path.
These paths both need access to the CRTC adjusted mode in order for the
proper dividers to be set for ALSA, and the scrambler state to be
reinstated properly for hotplug.
Let's copy this mode into our private encoder structure and reference it
from there when needed. Since that part is shared between KMS and other
paths, we need to protect it using our mutex.
Link: https://lore.kernel.org/all/YWgteNaNeaS9uWDe@phenom.ffwll.local/
Link: https://lore.kernel.org/r/20211025141113.702757-7-maxime@cerno.tech
Fixes: bb7d785688 ("drm/vc4: Add HDMI audio support")
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
The vc4 HDMI controller registers into the KMS, CEC and ALSA
frameworks.
However, no particular care is done to prevent the concurrent execution
of different framework hooks from happening at the same time.
In order to protect against that scenario, let's introduce a mutex that
relevant ALSA and KMS hooks will need to take to prevent concurrent
execution.
CEC is left out at the moment though, since the .get_modes and .detect
KMS hooks, when running cec_s_phys_addr_from_edid, can end up calling
CEC's .adap_enable hook. This introduces some reentrancy that isn't easy
to deal with properly.
The CEC hooks also don't share much state with the rest of the driver:
the registers are entirely separate, we don't share any variable, the
only thing that can conflict is the CEC clock divider setup that can be
affected by a mode set.
However, after discussing it, it looks like CEC should be able to
recover from this if it was to happen.
Link: https://lore.kernel.org/r/20211025141113.702757-6-maxime@cerno.tech
Fixes: bb7d785688 ("drm/vc4: Add HDMI audio support")
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
The vc4 HDMI driver has multiple path shared between the CEC, ALSA and
KMS frameworks, plus two interrupt handlers (CEC and hotplug) that will
read and modify a number of registers.
Even though not bug has been reported so far, it's definitely unsafe, so
let's just add a spinlock to protect the register access of the HDMI
controller.
Link: https://lore.kernel.org/r/20211025141113.702757-5-maxime@cerno.tech
Fixes: c8b75bca92 ("drm/vc4: Add KMS support for Raspberry Pi.")
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
The vc4_hdmi_audio_prepare function and the functions it's calling have
in several occurences multiple dereferences of either the sample rate or
the number of channels.
It turns out that these variables are also passed through the hdmi codec
parameters structure. Convert all the users to use this structure, and
if it's used multiple times use a variable to store it instead of
dereferencing it every time.
Reviewed-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20210707093632.1468127-1-maxime@cerno.tech
