On 10/07/2015 05:48 PM, Russell King - ARM Linux wrote:
> On Wed, Oct 07, 2015 at 12:05:37PM +0800, Yakir Yang wrote:
>>
>> On 08/09/2015 12:04 AM, Russell King wrote:
>>> The dw_hdmi enable/disable handling is particularly weak in several
>>> regards:
>>> * The hotplug interrupt could call hdmi_poweron() or hdmi_poweroff()
>>> while DRM is setting a mode, which could race with a mode being set.
>>> * Hotplug will always re-enable the phy whenever it detects an active
>>> hotplug signal, even if DRM has disabled the output.
>>>
>>> Resolve all of these by introducing a mutex to prevent races, and a
>>> state-tracking bool so we know whether DRM wishes the output to be
>>> enabled. We choose to use our own mutex rather than ->struct_mutex
>>> so that we can still process interrupts in a timely fashion.
>>>
>>> Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
>>> ---
>>> drivers/gpu/drm/bridge/dw_hdmi.c | 29 ++++++++++++++++++++++-------
>>> 1 file changed, 22 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c
>>> b/drivers/gpu/drm/bridge/dw_hdmi.c
>>> index 7b8a4e942a71..0ee188930d26 100644
>>> --- a/drivers/gpu/drm/bridge/dw_hdmi.c
>>> +++ b/drivers/gpu/drm/bridge/dw_hdmi.c
>>> @@ -125,6 +125,9 @@ struct dw_hdmi {
>>> bool sink_is_hdmi;
>>> bool sink_has_audio;
>>> + struct mutex mutex; /* for state below and previous_mode */
>>> + bool disabled; /* DRM has disabled our bridge */
>>> +
>>> spinlock_t audio_lock;
>>> struct mutex audio_mutex;
>>> unsigned int sample_rate;
>>> @@ -1389,8 +1392,12 @@ static void dw_hdmi_bridge_mode_set(struct
>>> drm_bridge *bridge,
>>> {
>>> struct dw_hdmi *hdmi = bridge->driver_private;
>>> + mutex_lock(&hdmi->mutex);
>>> +
>>> /* Store the display mode for plugin/DKMS poweron events */
>>> memcpy(&hdmi->previous_mode, mode, sizeof(hdmi->previous_mode));
>>> +
>>> + mutex_unlock(&hdmi->mutex);
>>> }
>>> static bool dw_hdmi_bridge_mode_fixup(struct drm_bridge *bridge,
>>> @@ -1404,14 +1411,20 @@ static void dw_hdmi_bridge_disable(struct
>>> drm_bridge *bridge)
>>> {
>>> struct dw_hdmi *hdmi = bridge->driver_private;
>>> + mutex_lock(&hdmi->mutex);
>>> + hdmi->disabled = true;
>>> dw_hdmi_poweroff(hdmi);
>>> + mutex_unlock(&hdmi->mutex);
>>> }
>>> static void dw_hdmi_bridge_enable(struct drm_bridge *bridge)
>>> {
>>> struct dw_hdmi *hdmi = bridge->driver_private;
>>> + mutex_lock(&hdmi->mutex);
>>> dw_hdmi_poweron(hdmi);
>>> + hdmi->disabled = false;
>>> + mutex_unlock(&hdmi->mutex);
>>> }
>>> static void dw_hdmi_bridge_nop(struct drm_bridge *bridge)
>>> @@ -1534,20 +1547,20 @@ static irqreturn_t dw_hdmi_irq(int irq, void
>>> *dev_id)
>>> phy_int_pol = hdmi_readb(hdmi, HDMI_PHY_POL0);
>>> if (intr_stat & HDMI_IH_PHY_STAT0_HPD) {
>>> + hdmi_modb(hdmi, ~phy_int_pol, HDMI_PHY_HPD, HDMI_PHY_POL0);
>>> + mutex_lock(&hdmi->mutex);
>>> if (phy_int_pol & HDMI_PHY_HPD) {
>>> dev_dbg(hdmi->dev, "EVENT=plugin\n");
>>> - hdmi_modb(hdmi, 0, HDMI_PHY_HPD, HDMI_PHY_POL0);
>>> -
>>> - dw_hdmi_poweron(hdmi);
>>> + if (!hdmi->disabled)
>>> + dw_hdmi_poweron(hdmi);
>>> } else {
>>> dev_dbg(hdmi->dev, "EVENT=plugout\n");
>>> - hdmi_modb(hdmi, HDMI_PHY_HPD, HDMI_PHY_HPD,
>>> - HDMI_PHY_POL0);
>>> -
>>> - dw_hdmi_poweroff(hdmi);
>>> + if (!hdmi->disabled)
>>> + dw_hdmi_poweroff(hdmi);
>> Just like my reply on 08/12, I thought this could be removed, so
>> poweron/poweroff would only be called with bridge->enable/
>> bridge->disable, them maybe no need mutex here.
> The bridge enable/disable methods do not get called on hotplug changes.
>
> [ 1.363011] dwhdmi-imx 120000.hdmi: Detected HDMI controller
> 0x13:0xa:0xa0:0xc1
> [ 1.371341] dwhdmi-imx 120000.hdmi: dw_hdmi_irq(I:RX----,HPD P:RX3210,HPD
> S:RX----,HPD)
> [ 1.381345] imx-drm display-subsystem: bound 120000.hdmi (ops
> dw_hdmi_imx_ops)
> [ 1.448691] dwhdmi-imx 120000.hdmi: dw_hdmi_bridge_disable()
> [ 1.450963] dwhdmi-imx 120000.hdmi: dw_hdmi_bridge_enable()
>
> and then unplugging and re-plugging the HDMI cable:
>
> [ 68.307505] dwhdmi-imx 120000.hdmi: dw_hdmi_irq(I:RX----,HPD P:RX3210,---
> S:RX----,---)
> [ 73.813970] dwhdmi-imx 120000.hdmi: dw_hdmi_irq(I:RX----,HPD P:RX3210,HPD
> S:RX----,HPD)
>
> As you can see, during the period of disconnection for five seconds,
> dw_hdmi_bridge_disable() was not called.
>
> So, without the code above, we'd be needlessly wasting power with the
> bridge enabled, trying to drive a disconnected display.
Strangely, I do see bridge enable/disable in my side, past the log and
dump_stack bellow.
And I guess your HDMI maybe not really hot pluged, could you confirm
that the "status"
of HDMI display card have been changed between "connected" and
"disconnected".
Do see bridge_disable when I unpluging the HDMI cable
[ 16.358717] dwhdmi-rockchip ff980000.hdmi: EVENT=plugout
[ 20.613221] [<c010e030>] (unwind_backtrace) from [<c010a4e0>]
(show_stack+0x20/0x24)
[ 20.631561] [<c010a4e0>] (show_stack) from [<c0896828>]
(dump_stack+0x70/0x8c)
[ 20.649337] [<c0896828>] (dump_stack) from [<c0414038>]
(dw_hdmi_bridge_disable+0x1c/0x88)
[ 20.668178] [<c0414038>] (dw_hdmi_bridge_disable) from [<c03e3888>]
(drm_encoder_disable+0x34/0x78)
[ 20.687857] [<c03e3888>] (drm_encoder_disable) from [<c03e3b1c>]
(__drm_helper_disable_unused_functions+0x68/0xe4)
[ 20.708975] [<c03e3b1c>] (__drm_helper_disable_unused_functions) from
[<c03e4320>] (drm_crtc_helper_set_config+0x128/0x85c)
[ 20.731180] [<c03e4320>] (drm_crtc_helper_set_config) from
[<c03f5e3c>] (drm_mode_set_config_internal+0x58/0xdc)
[ 20.752507] [<c03f5e3c>] (drm_mode_set_config_internal) from
[<c0405ed0>] (commit_crtc_state+0x124/0x1ec)
[ 20.773342] [<c0405ed0>] (commit_crtc_state) from [<c04055d4>]
(atomic_commit.isra.3+0x5c/0xc8)
[ 20.793397] [<c04055d4>] (atomic_commit.isra.3) from [<c040565c>]
(drm_atomic_commit+0x1c/0x20)
[ 20.813467] [<c040565c>] (drm_atomic_commit) from [<c03fa480>]
(drm_mode_setcrtc+0x324/0x3e4)
[ 20.833379] [<c03fa480>] (drm_mode_setcrtc) from [<c03eb320>]
(drm_ioctl+0x304/0x478)
[ 20.852557] [<c03eb320>] (drm_ioctl) from [<c021f024>]
(do_vfs_ioctl+0x494/0x5a8)
[ 20.871377] [<c021f024>] (do_vfs_ioctl) from [<c021f194>]
(SyS_ioctl+0x5c/0x84)
[ 20.890038] [<c021f194>] (SyS_ioctl) from [<c010646c>]
(__sys_trace_return+0x0/0x14)
[ 16.890157] ------- YAKIR: dw_hdmi_bridge_disable:1656
[ 16.897907] ------- YAKIR: dw_hdmi_poweroff:1631
Also see bridge have been disabled once before try to bridge_enable when
I try re-plugging the HDMI cable
[ 20.494292] dwhdmi-rockchip ff980000.hdmi: EVENT=plugin
[ 12.599389] [<c010e030>] (unwind_backtrace) from [<c010a4e0>]
(show_stack+0x20/0x24)
[ 12.612238] [<c010a4e0>] (show_stack) from [<c0896828>]
(dump_stack+0x70/0x8c)
[ 12.624609] [<c0896828>] (dump_stack) from [<c0414038>]
(dw_hdmi_bridge_disable+0x1c/0x88)
[ 12.638055] [<c0414038>] (dw_hdmi_bridge_disable) from [<c03e3dd4>]
(drm_crtc_helper_set_mode+0x20c/0x4e0)
[ 12.652878] [<c03e3dd4>] (drm_crtc_helper_set_mode) from [<c03e47ec>]
(drm_crtc_helper_set_config+0x5f4/0x85c)
[ 12.668019] [<c03e47ec>] (drm_crtc_helper_set_config) from
[<c03f5e3c>] (drm_mode_set_config_internal+0x58/0xdc)
[ 12.683442] [<c03f5e3c>] (drm_mode_set_config_internal) from
[<c0405ed0>] (commit_crtc_state+0x124/0x1ec)
[ 12.698287] [<c0405ed0>] (commit_crtc_state) from [<c04055d4>]
(atomic_commit.isra.3+0x5c/0xc8)
[ 12.712295] [<c04055d4>] (atomic_commit.isra.3) from [<c040565c>]
(drm_atomic_commit+0x1c/0x20)
[ 12.726258] [<c040565c>] (drm_atomic_commit) from [<c03fa480>]
(drm_mode_setcrtc+0x324/0x3e4)
[ 12.740226] [<c03fa480>] (drm_mode_setcrtc) from [<c03eb320>]
(drm_ioctl+0x304/0x478)
[ 12.753651] [<c03eb320>] (drm_ioctl) from [<c021f024>]
(do_vfs_ioctl+0x494/0x5a8)
[ 12.766794] [<c021f024>] (do_vfs_ioctl) from [<c021f194>]
(SyS_ioctl+0x5c/0x84)
[ 12.779861] [<c021f194>] (SyS_ioctl) from [<c010646c>]
(__sys_trace_return+0x0/0x14)
[ 21.059320] ------- YAKIR: dw_hdmi_bridge_disable:1656
[ 21.068272] ------- YAKIR: dw_hdmi_poweroff:1631
[ 21.076714] rockchip-vop ff930000.vop: start latency exceeded, new
value 9333 ns
[ 21.088037] rockchip-vop ff930000.vop: Attached to iommu domain
[ 12.871336] [<c010e030>] (unwind_backtrace) from [<c010a4e0>]
(show_stack+0x20/0x24)
[ 12.882067] [<c010a4e0>] (show_stack) from [<c0896828>]
(dump_stack+0x70/0x8c)
[ 12.892311] [<c0896828>] (dump_stack) from [<c0414134>]
(dw_hdmi_bridge_enable+0x3c/0xf28)
[ 12.903569] [<c0414134>] (dw_hdmi_bridge_enable) from [<c03e3ff4>]
(drm_crtc_helper_set_mode+0x42c/0x4e0)
[ 12.916226] [<c03e3ff4>] (drm_crtc_helper_set_mode) from [<c03e47ec>]
(drm_crtc_helper_set_config+0x5f4/0x85c)
[ 12.929450] [<c03e47ec>] (drm_crtc_helper_set_config) from
[<c03f5e3c>] (drm_mode_set_config_internal+0x58/0xdc)
[ 12.942883] [<c03f5e3c>] (drm_mode_set_config_internal) from
[<c0405ed0>] (commit_crtc_state+0x124/0x1ec)
[ 12.955784] [<c0405ed0>] (commit_crtc_state) from [<c04055d4>]
(atomic_commit.isra.3+0x5c/0xc8)
[ 12.967753] [<c04055d4>] (atomic_commit.isra.3) from [<c040565c>]
(drm_atomic_commit+0x1c/0x20)
[ 12.979705] [<c040565c>] (drm_atomic_commit) from [<c03fa480>]
(drm_mode_setcrtc+0x324/0x3e4)
[ 12.991568] [<c03fa480>] (drm_mode_setcrtc) from [<c03eb320>]
(drm_ioctl+0x304/0x478)
[ 13.002817] [<c03eb320>] (drm_ioctl) from [<c021f024>]
(do_vfs_ioctl+0x494/0x5a8)
[ 13.013766] [<c021f024>] (do_vfs_ioctl) from [<c021f194>]
(SyS_ioctl+0x5c/0x84)
[ 13.024655] [<c021f194>] (SyS_ioctl) from [<c010646c>]
(__sys_trace_return+0x0/0x14)
[ 21.114556] ------- YAKIR: dw_hdmi_bridge_enable:1664
[ 21.122889] ------- YAKIR: dw_hdmi_poweron:1625
- Yakir
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