From: Lee Jones <lee.jones@linaro.org>
To: alokc@codeaurora.org, agross@kernel.org, robh+dt@kernel.org,
mark.rutland@arm.com, bjorn.andersson@linaro.org,
vkoul@kernel.org, wsa@the-dreams.de
Cc: devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org,
Lee Jones <lee.jones@linaro.org>,
linux-arm-kernel@lists.infradead.org
Subject: [RESEND v3 1/1] i2c: qcom-geni: Provide an option to disable DMA processing
Date: Thu, 5 Sep 2019 15:41:22 +0100 [thread overview]
Message-ID: <20190905144122.5689-1-lee.jones@linaro.org> (raw)
We have a production-level laptop (Lenovo Yoga C630) which is exhibiting
a rather horrific bug. When I2C HID devices are being scanned for at
boot-time the QCom Geni based I2C (Serial Engine) attempts to use DMA.
When it does, the laptop reboots and the user never sees the OS.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
drivers/i2c/busses/i2c-qcom-geni.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
index a89bfce5388e..17abf60c94ae 100644
--- a/drivers/i2c/busses/i2c-qcom-geni.c
+++ b/drivers/i2c/busses/i2c-qcom-geni.c
@@ -355,11 +355,13 @@ static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
{
dma_addr_t rx_dma;
unsigned long time_left;
- void *dma_buf;
+ void *dma_buf = NULL;
struct geni_se *se = &gi2c->se;
size_t len = msg->len;
- dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
+ if (!of_machine_is_compatible("lenovo,yoga-c630"))
+ dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
+
if (dma_buf)
geni_se_select_mode(se, GENI_SE_DMA);
else
@@ -394,11 +396,13 @@ static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
{
dma_addr_t tx_dma;
unsigned long time_left;
- void *dma_buf;
+ void *dma_buf = NULL;
struct geni_se *se = &gi2c->se;
size_t len = msg->len;
- dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
+ if (!of_machine_is_compatible("lenovo,yoga-c630"))
+ dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
+
if (dma_buf)
geni_se_select_mode(se, GENI_SE_DMA);
else
--
2.17.1
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next reply other threads:[~2019-09-05 14:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-05 14:41 Lee Jones [this message]
2019-09-05 18:20 ` [RESEND v3 1/1] i2c: qcom-geni: Provide an option to disable DMA processing Wolfram Sang
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