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 >
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