linux_dsm_epyc7002/drivers
Samuel Holland 215be713d0
drm/sun4i: dsi: Remove incorrect use of runtime PM
The driver currently uses runtime PM to perform some of the module
initialization and cleanup. This has three problems:

1) There is no Kconfig dependency on CONFIG_PM, so if runtime PM is
   disabled, the driver will not work at all, since the module will
   never be initialized.

2) The driver does not ensure that the device is suspended when
   sun6i_dsi_probe() fails or when sun6i_dsi_remove() is called. It
   simply disables runtime PM. From the docs of pm_runtime_disable():

      The device can be either active or suspended after its runtime PM
      has been disabled.

   And indeed, the device will likely still be active if sun6i_dsi_probe
   fails. For example, if the panel driver is not yet loaded, we have
   the following sequence:

   sun6i_dsi_probe()
      pm_runtime_enable()
      mipi_dsi_host_register()
         of_mipi_dsi_device_add(child)
            ...device_add()...
               __device_attach()
                 pm_runtime_get_sync(dev->parent) -> Causes resume
                 bus_for_each_drv()
                    __device_attach_driver() -> No match for panel
                 pm_runtime_put(dev->parent) -> Async idle request
      component_add()
         __component_add()
            try_to_bring_up_masters()
               try_to_bring_up_master()
                  sun4i_drv_bind()
                     component_bind_all()
                        component_bind()
                           sun6i_dsi_bind() -> Fails with -EPROBE_DEFER
      mipi_dsi_host_unregister()
      pm_runtime_disable()
         __pm_runtime_disable()
            __pm_runtime_barrier() -> Idle request is still pending
               cancel_work_sync()  -> DSI host is *not* suspended!

   Since the device is not suspended, the clock and regulator are never
   disabled. The imbalance causes a WARN at devres free time.

3) The driver relies on being suspended when sun6i_dsi_encoder_enable()
   is called. The resume callback has a comment that says:

      Some part of it can only be done once we get a number of
      lanes, see sun6i_dsi_inst_init

   And then part of the resume callback only runs if dsi->device is not
   NULL (that is, if sun6i_dsi_attach() has been called). However, as
   the above call graph shows, the resume callback is guaranteed to be
   called before sun6i_dsi_attach(); it is called before child devices
   get their drivers attached.

   Therefore, part of the controller initialization will only run if the
   device is suspended between the calls to mipi_dsi_host_register() and
   component_add() (which ends up calling sun6i_dsi_encoder_enable()).
   Again, as shown by the above call graph, this is not the case. It
   appears that the controller happens to work because it is still
   initialized by the bootloader.

   Because the connector is hardcoded to always be connected, the
   device's runtime PM reference is not dropped until system suspend,
   when sun4i_drv_drm_sys_suspend() ends up calling
   sun6i_dsi_encoder_disable(). However, that is done as a system sleep
   PM hook, and at that point the system PM core has already taken
   another runtime PM reference, so sun6i_dsi_runtime_suspend() is
   not called. Likewise, by the time the PM core releases its reference,
   sun4i_drv_drm_sys_resume() has already re-enabled the encoder.

   So after system suspend and resume, we have *still never called*
   sun6i_dsi_inst_init(), and now that the rest of the display pipeline
   has been reset, the DSI host is unable to communicate with the panel,
   causing VBLANK timeouts.

Fix all of these issues by inlining the runtime PM hooks into the
encoder enable/disable functions, which are guaranteed to run after a
panel is attached. This allows sun6i_dsi_inst_init() to be called
unconditionally. Furthermore, this causes the hardware to be turned off
during system suspend and reinitialized on resume, which was not
happening before.

Fixes: 133add5b5a ("drm/sun4i: Add Allwinner A31 MIPI-DSI controller support")
Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20200211072858.30784-4-samuel@sholland.org
2020-02-14 16:25:59 +01:00
..
accessibility
acpi i915 features for v5.6: 2019-12-27 15:25:04 +10:00
amba
android binder: fix incorrect calculation for num_valid 2019-12-14 09:10:47 +01:00
ata pci-v5.5-changes 2019-12-03 13:58:22 -08:00
atm
auxdisplay drm-misc-next for v5.6: 2019-12-17 13:57:54 +01:00
base Merge branch 'remove-ksys-mount-dup' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux 2019-12-15 11:36:12 -08:00
bcma
block xen: branch for v5.5-rc2 2019-12-15 12:24:44 -08:00
bluetooth
bus Few ti-sysc related fixes for v5.5 merge window 2019-12-06 08:26:50 -08:00
cdrom
char drm msm + fixes for 5.5-rc1 2019-12-06 10:28:09 -08:00
clk ARM: SoC platform updates 2019-12-05 11:38:40 -08:00
clocksource Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-12-03 12:20:25 -08:00
connector
counter
cpufreq cpufreq: tegra: Changes for v5.5-rc1 2019-12-06 08:28:13 -08:00
cpuidle cpuidle: Drop unnecessary type cast in cpuidle_poll_time() 2019-12-12 17:56:08 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2019-12-02 17:23:21 -08:00
dax libnvdimm for 5.5 2019-12-01 18:43:25 -08:00
dca
devfreq PM / devfreq: Use PM QoS for sysfs min/max_freq 2019-12-09 12:19:16 +09:00
dio
dma
dma-buf drm-misc-next for v5.6: 2020-01-03 11:43:44 +10:00
edac
eisa
extcon
firewire FireWire (IEEE 1394) subsystem updates: 2019-12-02 14:13:00 -08:00
firmware treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
fpga
fsi
gnss
gpio gpio: pca953x: tighten up indentation 2019-12-04 19:44:14 -08:00
gpu drm/sun4i: dsi: Remove incorrect use of runtime PM 2020-02-14 16:25:59 +01:00
greybus
hid drm-misc-next for v5.6: 2019-12-17 13:57:54 +01:00
hsi
hv Merge branch 'akpm' (patches from Andrew) 2019-12-01 20:36:41 -08:00
hwmon compat_ioctl: remove most of fs/compat_ioctl.c 2019-12-01 13:46:15 -08:00
hwspinlock
hwtracing compat_ioctl: remove most of fs/compat_ioctl.c 2019-12-01 13:46:15 -08:00
i2c i2c: remove i2c_new_dummy() API 2019-12-10 23:15:09 +01:00
i3c
ide compat_ioctl: remove most of fs/compat_ioctl.c 2019-12-01 13:46:15 -08:00
idle
iio First set of fixes for IIO in the 5.5 cycle. 2019-12-09 09:27:52 +01:00
infiniband Pull request for 5.5-rc2 2019-12-15 14:58:13 -08:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2019-12-07 18:33:01 -08:00
interconnect interconnect: qcom: msm8974: Walk the list safely on node removal 2019-12-12 10:28:54 +01:00
iommu pci-v5.5-changes 2019-12-03 13:58:22 -08:00
ipack
irqchip pci-v5.5-changes 2019-12-03 13:58:22 -08:00
isdn compat_ioctl: remove most of fs/compat_ioctl.c 2019-12-01 13:46:15 -08:00
leds Merge tag 'leds-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-leds 2019-12-01 16:09:28 -08:00
lightnvm
macintosh
mailbox mailbox changes for v5.5 2019-12-01 18:42:02 -08:00
mcb
md for-linus-20191212 2019-12-13 14:27:19 -08:00
media drm-misc-next for v5.6: 2019-12-17 13:57:54 +01:00
memory memory: tegra: Fixes for v5.5-rc1 2019-12-06 08:28:51 -08:00
memstick pci-v5.5-changes 2019-12-03 13:58:22 -08:00
message
mfd mfd: intel_soc_pmic: Rename pwm_backlight pwm-lookup to pwm_pmic_backlight 2019-12-17 11:24:47 +01:00
misc drm-misc-next for v5.6: 2019-12-17 13:57:54 +01:00
mmc
mtd TTY/Serial patches for 5.5-rc1 2019-12-03 14:09:14 -08:00
mux
net treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
nfc
ntb Add Hygon Device ID to the AMD NTB device driver 2019-12-07 18:38:17 -08:00
nubus
nvdimm libnvdimm for 5.5 2019-12-01 18:43:25 -08:00
nvme for-linus-20191212 2019-12-13 14:27:19 -08:00
nvmem ARM: SoC-related driver updates 2019-12-05 11:43:31 -08:00
of of/platform: Unconditionally pause/resume sync state during kernel init 2019-12-12 18:39:52 -06:00
opp
oprofile
parisc
parport
pci PCI: rockchip: Fix IO outbound ATU register number 2019-12-12 15:25:37 -06:00
pcmcia
perf
phy ARM: SoC-related driver updates 2019-12-05 11:43:31 -08:00
pinctrl Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-12-03 09:29:50 -08:00
platform chrome platform changes for v5.5 2019-12-03 14:37:12 -08:00
pnp
power Additional power management updates for 5.5-rc1 2019-12-04 10:48:09 -08:00
powercap
pps
ps3
ptp
pwm pwm: Changes for v5.5-rc1 2019-12-05 11:28:14 -08:00
rapidio drivers/rapidio/rio-access.c: fix missing include of <linux/rio_drv.h> 2019-12-04 19:44:13 -08:00
ras
regulator
remoteproc
reset ARM: SoC-related driver updates 2019-12-05 11:43:31 -08:00
rpmsg rpmsg updates for v5.5 2019-12-01 18:39:24 -08:00
rtc RTC for 5.5 2019-12-03 13:31:08 -08:00
s390 treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
sbus
scsi SCSI fixes on 20191214 2019-12-14 12:51:57 -08:00
sfi
sh
siox
slimbus
soc ARM: SoC fixes 2019-12-06 14:19:37 -08:00
soundwire
spi
spmi
ssb
staging drm-misc-next for v5.6: 2019-12-17 13:57:54 +01:00
target treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
tc
tee drm-misc-next for v5.6: 2019-12-17 13:57:54 +01:00
thermal thermal: power_allocator: Fix Kconfig warning 2019-12-07 21:49:06 +08:00
thunderbolt
tty TTY/Serial patches for 5.5-rc1 2019-12-03 14:09:14 -08:00
uio
usb USB driver fixes for 5.5-rc2 2019-12-14 12:40:39 -08:00
vfio VFIO updates for v5.5-rc1 2019-12-07 14:51:04 -08:00
vhost Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-12-08 13:28:11 -08:00
video video: fbdev: nvidia: clean up indentation issues and comment block 2020-01-15 17:31:53 +01:00
virt compat_ioctl: remove most of fs/compat_ioctl.c 2019-12-01 13:46:15 -08:00
virtio virtio_balloon: divide/multiply instead of shifts 2019-12-11 08:14:07 -05:00
visorbus
vlynq
vme
w1
watchdog linux-watchdog 5.5-rc1 tag 2019-12-01 18:01:03 -08:00
xen drm-misc-next for v5.6: 2019-12-17 13:57:54 +01:00
zorro
Kconfig
Makefile