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| author | Douglas Anderson <dianders@chromium.org> | 2020-06-19 14:20:01 -0700 |
|---|---|---|
| committer | Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> | 2020-07-02 17:49:00 +0300 |
| commit | 7187bf7f6297a8cfc74512a4493e06028626482d (patch) | |
| tree | 05a172562424379fd81570ef737d4fb15c282bcb /drivers/char | |
| parent | 72d0556dca39f45eca6c4c085e9eb0fc70aec025 (diff) | |
| download | linux-7187bf7f6297a8cfc74512a4493e06028626482d.tar.bz2 | |
tpm_tis_spi: Prefer async probe
On a Chromebook I'm working on I noticed a big (~1 second) delay
during bootup where nothing was happening. Right around this big
delay there were messages about the TPM:
[ 2.311352] tpm_tis_spi spi0.0: TPM ready IRQ confirmed on attempt 2
[ 3.332790] tpm_tis_spi spi0.0: Cr50 firmware version: ...
I put a few printouts in and saw that tpm_tis_spi_init() (specifically
tpm_chip_register() in that function) was taking the lion's share of
this time, though ~115 ms of the time was in cr50_print_fw_version().
Let's make a one-line change to prefer async probe for tpm_tis_spi.
There's no reason we need to block other drivers from probing while we
load.
NOTES:
* It's possible that other hardware runs through the init sequence
faster than Cr50 and this isn't such a big problem for them.
However, even if they are faster they are still doing _some_
transfers over a SPI bus so this should benefit everyone even if to
a lesser extent.
* It's possible that there are extra delays in the code that could be
optimized out. I didn't dig since once I enabled async probe they
no longer impacted me.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/tpm/tpm_tis_spi_main.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm_tis_spi_main.c b/drivers/char/tpm/tpm_tis_spi_main.c index 8d2c581a93c6..3856f6ebcb34 100644 --- a/drivers/char/tpm/tpm_tis_spi_main.c +++ b/drivers/char/tpm/tpm_tis_spi_main.c @@ -287,6 +287,7 @@ static struct spi_driver tpm_tis_spi_driver = { .pm = &tpm_tis_pm, .of_match_table = of_match_ptr(of_tis_spi_match), .acpi_match_table = ACPI_PTR(acpi_tis_spi_match), + .probe_type = PROBE_PREFER_ASYNCHRONOUS, }, .probe = tpm_tis_spi_driver_probe, .remove = tpm_tis_spi_remove, |