Messages in this thread | | | Date | Tue, 23 Oct 2012 17:32:57 -0700 | From | Christopher Heiny <> | Subject | Re: [RFC PATCH 02/06] input/rmi4: Core files |
| |
On 10/23/2012 05:11 PM, Dmitry Torokhov wrote: > On Tuesday, October 23, 2012 04:46:28 PM Christopher Heiny wrote: >> On 10/11/2012 01:13 AM, Dmitry Torokhov wrote: >>> On Thu, Oct 11, 2012 at 04:15:56AM +0000, Christopher Heiny wrote: >>>> On Thursday, October 11, 2012 02:21:53 AM you wrote: >>>>> On Sat, Oct 6, 2012 at 6:09 AM, Christopher Heiny <cheiny@synaptics.com> > wrote:
[snip]
>>>>>> +static int process_interrupt_requests(struct rmi_device *rmi_dev) >>>>>> +{ >>>>>> + struct rmi_driver_data *data = dev_get_drvdata(&rmi_dev->dev); >>>>>> + struct device *dev = &rmi_dev->dev; >>>>>> + struct rmi_function_container *entry; >>>>>> + u8 irq_status[data->num_of_irq_regs]; >>>>> >>>>> Looking at this... >>>>> >>>>> What does the data->num_of_irq_regs actually contain? >>>>> >>>>> I just fear that it is something constant like always 2 or always 4, >>>>> so there is actually, in reality, a 16 or 32 bit register hiding in >>>>> there. >>>>> >>>>> In that case what you should do is to represent it as a u16 or u32 here, >>>>> just or the bits into a status word, and then walk over that status >>>>> word with something like ffs(bitword); ... >>>> >>>> Nope, it's not constant. In theory, and RMI4 based sensor can have up >>>> to 128 functions (in practice, it's far fewer), and each function can >>>> have as many as 7 interrupts. So the number of IRQ registers can vary >>>> from RMI4 sensor to RMI4 sensor, and needs to be computed during the >>>> scan of the product descriptor table. >>> >>> Is it a good idea to have it on stack then? Should it be part of >>> rmi_device instead? >> >> It's not coming off the stack. We're allocating it via devm_kzalloc() >> in rmi_driver_probe(). > > No, look at the part of the code that was quoted. "u8 irq_status[data- > num_of_irq_regs];" is on stack.
Sorry - I thought you were referring to data->num_of_irq_regs rather than irq_status. We'll move that.
| |