lkml.org 
[lkml]   [2019]   [Sep]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RESEND v3 1/1] i2c: qcom-geni: Provide an option to disable DMA processing
Date
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
\
 
 \ /
  Last update: 2019-09-05 16:42    [W:0.037 / U:4.248 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site