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 <[email protected]>
---
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
On Thu, Sep 05, 2019 at 03:41:22PM +0100, Lee Jones wrote:
> 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.
$subject is still wrong. And a paragraph that you are/were debugging the
root cause but to no avail so DMA gets disabled for now would be good for a
hotfix this late in the cycle.
>
> Signed-off-by: Lee Jones <[email protected]>
> ---
> 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
>