On Mon, 06 Jan 2020 04:04:18 +0300, Dmitry Osipenko wrote: > System shutdown may happen with interrupts being disabled and in this case > I2C core rejects transfers if atomic transfer isn't supported by driver. > > There were several occurrences where I found my Nexus 7 completely > discharged despite of being turned off and then one day I spotted this in > the log: > > reboot: Power down > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 1 at drivers/i2c/i2c-core.h:40 i2c_transfer+0x95/0x9c > No atomic I2C transfer handler for 'i2c-1' > Modules linked in: tegra30_devfreq > CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 5.4.0-next-20191202-00120-gf7ecd80fb803-dirty #3195 > Hardware name: NVIDIA Tegra SoC (Flattened Device Tree) > [<c010e4b5>] (unwind_backtrace) from [<c010a0fd>] (show_stack+0x11/0x14) > [<c010a0fd>] (show_stack) from [<c09995e5>] (dump_stack+0x85/0x94) > [<c09995e5>] (dump_stack) from [<c011f3d1>] (__warn+0xc1/0xc4) > [<c011f3d1>] (__warn) from [<c011f691>] (warn_slowpath_fmt+0x61/0x78) > [<c011f691>] (warn_slowpath_fmt) from [<c069a8dd>] (i2c_transfer+0x95/0x9c) > [<c069a8dd>] (i2c_transfer) from [<c05667f1>] (regmap_i2c_read+0x4d/0x6c) > [<c05667f1>] (regmap_i2c_read) from [<c0563601>] (_regmap_raw_read+0x99/0x1cc) > [<c0563601>] (_regmap_raw_read) from [<c0563757>] (_regmap_bus_read+0x23/0x38) > [<c0563757>] (_regmap_bus_read) from [<c056293d>] (_regmap_read+0x3d/0xfc) > [<c056293d>] (_regmap_read) from [<c0562d3b>] (_regmap_update_bits+0x87/0xc4) > [<c0562d3b>] (_regmap_update_bits) from [<c0563add>] (regmap_update_bits_base+0x39/0x50) > [<c0563add>] (regmap_update_bits_base) from [<c056fd39>] (max77620_pm_power_off+0x29/0x2c) > [<c056fd39>] (max77620_pm_power_off) from [<c013bbdd>] (__do_sys_reboot+0xe9/0x170) > [<c013bbdd>] (__do_sys_reboot) from [<c0101001>] (ret_fast_syscall+0x1/0x28) > Exception stack(0xde907fa8 to 0xde907ff0) > 7fa0: 00000000 00000000 fee1dead 28121969 4321fedc 00000000 > 7fc0: 00000000 00000000 00000000 00000058 00000000 00000000 00000000 00000000 > 7fe0: 0045adf0 bed9abb8 004444a0 b6c666d0 > ---[ end trace bdd18f87595b1a5e ]--- > > The atomic transferring is implemented by enforcing PIO mode for the > transfer and by polling interrupt status until transfer is completed or > failed. > > Now system shuts down properly every time. > > Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx> > --- > drivers/i2c/busses/i2c-tegra.c | 84 ++++++++++++++++++++++++++++------ > 1 file changed, 69 insertions(+), 15 deletions(-) Tested-by: Thierry Reding <treding@xxxxxxxxxx>
