| Message ID | 20221028145319.1.I87b119c576d486ad139faf1b7278d97e158aabe4@changeid (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915: Set PROBE_PREFER_ASYNCHRONOUS | expand |
diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c index 38460a0bd7cb..1cb1f87aea86 100644 --- a/drivers/gpu/drm/i915/i915_pci.c +++ b/drivers/gpu/drm/i915/i915_pci.c @@ -1371,7 +1371,10 @@ static struct pci_driver i915_pci_driver = { .probe = i915_pci_probe, .remove = i915_pci_remove, .shutdown = i915_pci_shutdown, - .driver.pm = &i915_pm_ops, + .driver = { + .pm = &i915_pm_ops, + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + }, }; int i915_pci_register_driver(void)
This driver often takes a good 100ms to start, but in some particularly bad cases takes more than 1 second. In surveying risk for this driver, I poked around for cross-device shared state, which can be a source of race conditions. GVT support (intel_gvt_devices) seems potentially suspect, but it has an appropriate mutex, and doesn't seem to care about ordering -- if devices are present when the kvmgt module loads, they'll get picked up; and if they probe later than kvmgt, they'll attach then. Additionally, I see past discussions about this patch [1], which concluded that there were problems at the time due to the way hdac_i915.c called request_module("i915") and expected it to complete probing [2]. Work has since been merged [3] to fix that problem. This driver was pinpointed as part of a survey of drivers that take more than 100ms in their initcall (i.e., are built in, and probing synchronously) on a lab of ChromeOS systems. [1] [RFC] i915: make the probe asynchronous https://lore.kernel.org/all/20180604053219.2040-1-feng.tang@intel.com/ [2] https://lore.kernel.org/all/s5hin4d1e3f.wl-tiwai@suse.de/ [3] Commit f9b54e1961c7 ("ALSA: hda/i915: Allow delayed i915 audio component binding") Signed-off-by: Brian Norris <briannorris@chromium.org> --- drivers/gpu/drm/i915/i915_pci.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)