From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexey Starikovskiy Subject: [PATCH] ACPI: EC: wait for last write gpe Date: Sat, 08 Nov 2008 21:42:30 +0300 Message-ID: <20081108184228.7154.51815.stgit@thinkpad> References: <4915C296.9030903@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from charybdis-ext.suse.de ([195.135.221.2]:39301 "EHLO emea5-mh.id5.novell.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751056AbYKHSmf (ORCPT ); Sat, 8 Nov 2008 13:42:35 -0500 In-Reply-To: <4915C296.9030903@suse.de> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: LenBrown Cc: Linux-acpi@vger.kernel.org There is a possibility that EC might break if next command is issued within 1 us after write or burst-disable command. This "possibility" was in EC driver for 3.5 years, after 451566f45a2e6cd10ba56e7220a9dd84ba3ef550. References: http://marc.info/?l=linux-acpi&m=122616284402886&w=4 Cc: Zhao Yakui Signed-off-by: Alexey Starikovskiy --- drivers/acpi/ec.c | 21 +++++++++++++-------- 1 files changed, 13 insertions(+), 8 deletions(-) diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c index e5dbe21..d6007ac 100644 --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -102,6 +102,7 @@ struct transaction { u8 command; u8 wlen; u8 rlen; + bool done; }; static struct acpi_ec { @@ -178,7 +179,7 @@ static int ec_transaction_done(struct acpi_ec *ec) unsigned long flags; int ret = 0; spin_lock_irqsave(&ec->curr_lock, flags); - if (!ec->curr || (!ec->curr->wlen && !ec->curr->rlen)) + if (!ec->curr || ec->curr->done) ret = 1; spin_unlock_irqrestore(&ec->curr_lock, flags); return ret; @@ -195,17 +196,20 @@ static void gpe_transaction(struct acpi_ec *ec, u8 status) acpi_ec_write_data(ec, *(ec->curr->wdata++)); --ec->curr->wlen; } else - /* false interrupt, state didn't change */ - ++ec->curr->irq_count; - + goto err; } else if (ec->curr->rlen > 0) { if ((status & ACPI_EC_FLAG_OBF) == 1) { *(ec->curr->rdata++) = acpi_ec_read_data(ec); - --ec->curr->rlen; + if (--ec->curr->rlen == 0) + ec->curr->done = true; } else - /* false interrupt, state didn't change */ - ++ec->curr->irq_count; - } + goto err; + } else if (ec->curr->wlen == 0 && (status & ACPI_EC_FLAG_IBF) == 0) + ec->curr->done = true; + goto unlock; +err: + /* false interrupt, state didn't change */ + ++ec->curr->irq_count; unlock: spin_unlock_irqrestore(&ec->curr_lock, flags); } @@ -265,6 +269,7 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, spin_lock_irqsave(&ec->curr_lock, tmp); /* following two actions should be kept atomic */ t->irq_count = 0; + t->done = false; ec->curr = t; acpi_ec_write_cmd(ec, ec->curr->command); if (ec->curr->command == ACPI_EC_COMMAND_QUERY)