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authorDouglas Anderson <dianders@chromium.org>2020-06-19 14:20:01 -0700
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2020-07-02 17:49:00 +0300
commit7187bf7f6297a8cfc74512a4493e06028626482d (patch)
tree05a172562424379fd81570ef737d4fb15c282bcb /drivers/char
parent72d0556dca39f45eca6c4c085e9eb0fc70aec025 (diff)
downloadlinux-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.c1
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,