| Message ID | 67bfa9b60bd689601554526d144b21d529f78a09.1349761836.git.len.brown@intel.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
Len Brown wrote: > By enlarging the GPE storm threshold back to 20, that laptop's > EC works fine with interrupt mode instead of polling mode. What would go wrong if the threshold were just increased to 20 on all models? Thanks, Jonathan -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Jonathan, On Tue, 9 Oct 2012 14:16:33 +0800 Jonathan Nieder <jrnieder@gmail.com> wrote: > Len Brown wrote: > > > By enlarging the GPE storm threshold back to 20, that laptop's > > EC works fine with interrupt mode instead of polling mode. > > What would go wrong if the threshold were just increased to 20 on all > models? Then some other platform will stop to work. https://bugzilla.kernel.org/show_bug.cgi?id=11892 The 26/30 and 27/30 patches are bound together to fix one bug. Some quote from description from the 26th patch: ACPI_EC_STORM_THRESHOLD was initially 20 when it's created, and was changed to 8 in 2.6.28 commit 06cf7d3c7 "ACPI: EC: lower interrupt storm threshold" to fix kernel bug 11892 by forcing the laptop in that bug to work in polling mode. Hope this answers your question. Thanks, Feng -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Feng Tang wrote: > Jonathan Nieder <jrnieder@gmail.com> wrote: >> What would go wrong if the threshold were just increased to 20 on all >> models? > > Then some other platform will stop to work. > https://bugzilla.kernel.org/show_bug.cgi?id=11892 > > The 26/30 and 27/30 patches are bound together to fix one bug. Some > quote from description from the 26th patch: > > ACPI_EC_STORM_THRESHOLD was initially 20 when it's created, and > was changed to 8 in 2.6.28 commit 06cf7d3c7 "ACPI: EC: lower interrupt storm > threshold" to fix kernel bug 11892 by forcing the laptop in that bug to > work in polling mode. > > Hope this answers your question. Thanks much. Yes, that clarifies. The magic numbers are not too thrilling. If the polling mode just doesn't work on the Clevo M720, why isn't the appropriate storm threshold 999999 or infinity rather than 20? Do we know why the polling mode doesn't work? Jonathan -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, 8 Oct 2012 23:59:07 -0700 Jonathan Nieder <jrnieder@gmail.com> wrote: > Feng Tang wrote: > > Jonathan Nieder <jrnieder@gmail.com> wrote: > > >> What would go wrong if the threshold were just increased to 20 on all > >> models? > > > > Then some other platform will stop to work. > > https://bugzilla.kernel.org/show_bug.cgi?id=11892 > > > > The 26/30 and 27/30 patches are bound together to fix one bug. Some > > quote from description from the 26th patch: > > > > ACPI_EC_STORM_THRESHOLD was initially 20 when it's created, and > > was changed to 8 in 2.6.28 commit 06cf7d3c7 "ACPI: EC: lower interrupt storm > > threshold" to fix kernel bug 11892 by forcing the laptop in that bug to > > work in polling mode. > > > > Hope this answers your question. > > Thanks much. Yes, that clarifies. > > The magic numbers are not too thrilling. If the polling mode just > doesn't work on the Clevo M720, why isn't the appropriate storm > threshold 999999 or infinity rather than 20? Do we know why the > polling mode doesn't work? I don't know why it doesn't work, if you check the https://bugzilla.kernel.org/show_bug.cgi?id=45151 you'll see the debugging model is test result --> patch --> 1-2 weeks + result --> patch --> 1-2 weeks + result ... over and over, which makes it difficult to root cause it but provide a workaround. And frankly speaking, I'm not sure if I can figure it out 100% even if I had that HW at hand. As per my understanding, EC is very tricky, as OS, ACPI FW, EC FW, BIOS will all access it without a global lock (in most cases), which makes it hard to work properly without race condition. Not mentioning its hardware may be broken. Thanks, Feng -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c index 615264c..a51df96 100644 --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -930,6 +930,17 @@ static int ec_flag_msi(const struct dmi_system_id *id) return 0; } +/* + * Clevo M720 notebook actually works ok with IRQ mode, if we lifted + * the GPE storm threshold back to 20 + */ +static int ec_enlarge_storm_threshold(const struct dmi_system_id *id) +{ + pr_debug("Setting the EC GPE storm threshold to 20\n"); + ec_storm_threshold = 20; + return 0; +} + static struct dmi_system_id __initdata ec_dmi_table[] = { { ec_skip_dsdt_scan, "Compal JFL92", { @@ -961,10 +972,13 @@ static struct dmi_system_id __initdata ec_dmi_table[] = { { ec_validate_ecdt, "ASUS hardware", { DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL}, + { + ec_enlarge_storm_threshold, "CLEVO hardware", { + DMI_MATCH(DMI_SYS_VENDOR, "CLEVO Co."), + DMI_MATCH(DMI_PRODUCT_NAME, "M720T/M730T"),}, NULL}, {}, }; - int __init acpi_ec_ecdt_probe(void) { acpi_status status;