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Message-ID: <CAN+gG=HQoyEXLGDQ38YOc_EMs5zj7whP7xNOR0VEd4EFsgKiqw@mail.gmail.com>
Date: Wed, 28 Mar 2012 11:31:26 +0200
From: Benjamin Tissoires <benjamin.tissoires@...il.com>
To: Henrik Rydberg <rydberg@...math.se>
Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>,
Jiri Kosina <jkosina@...e.cz>,
Stephane Chatty <chatty@...c.fr>, linux-input@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] HID: autoload hid-multitouch as needed
Hi Henrik,
I'll do the requested changes: no need to comment ;-)
Cheers,
Benjamin
On Wed, Mar 28, 2012 at 09:03, Henrik Rydberg <rydberg@...math.se> wrote:
> Hi Benjamin,
>
>> When the generic hid parsing of the report descriptors in hid-core
>> detects that the device contains the field ContactID, the device should
>> be handled by hid-multitouch, and hid-core should release it.
>> This patch implements a temporary fix for hid-core to automatically
>> call the loading of hid-multitouch. A better solution would involve
>> userspace.
>>
>> The code is inspired from what is done in the bttv module.
>>
>> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...c.fr>
>> ---
>>
>> Hi guys,
>>
>> I finally managed to find some time to resend this patch.
>
> Great, please find some comments inline.
>
>> drivers/hid/hid-core.c | 33 ++++++++++++++++++++++++++++++++-
>> include/linux/hid.h | 8 ++++++++
>> 2 files changed, 40 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
>> index 990fe19..a84221e 100644
>> --- a/drivers/hid/hid-core.c
>> +++ b/drivers/hid/hid-core.c
>> @@ -1210,6 +1210,31 @@ static struct bin_attribute dev_bin_attr_report_desc = {
>> .size = HID_MAX_DESCRIPTOR_SIZE,
>> };
>>
>> +#if defined(CONFIG_MODULES) && defined(MODULE)
>> +/* Loading of hid_multitouch. This is done from the kernel until we come up
>> + * with a more robust solution. */
>> +static void hid_request_hid_mt_module_async(struct work_struct *work)
>> +{
>> + request_module("hid-multitouch");
>> +}
>> +
>> +static void hid_request_hid_mt_module(struct hid_device *dev)
>> +{
>> + dev->request_hid_mt_module = 1;
>> + INIT_WORK(&dev->request_hid_mt_module_wk,
>> + hid_request_hid_mt_module_async);
>
> This init would probably be better off as a static declaration; after
> all, we do not need one workqueue per hid device.
>
>> + schedule_work(&dev->request_hid_mt_module_wk);
>> +}
>> +
>> +static void hid_flush_request_modules(struct hid_device *dev)
>> +{
>> + flush_work_sync(&dev->request_hid_mt_module_wk);
>> +}
>> +#else
>> +#define hid_request_hid_mt_module(dev)
>> +#define hid_flush_request_modules(dev)
>> +#endif /* CONFIG_MODULES */
>> +
>> int hid_connect(struct hid_device *hdev, unsigned int connect_mask)
>> {
>> static const char *types[] = { "Device", "Pointer", "Mouse", "Device",
>> @@ -1235,7 +1260,9 @@ int hid_connect(struct hid_device *hdev, unsigned int connect_mask)
>> connect_mask & HID_CONNECT_HIDINPUT_FORCE))
>> hdev->claimed |= HID_CLAIMED_INPUT;
>> if (hdev->quirks & HID_QUIRK_MULTITOUCH) {
>> - /* this device should be handled by hid-multitouch, skip it */
>> + /* this device should be handled by hid-multitouch, request
>> + * for hid-multitouch to be loaded and leave the device to it */
>> + hid_request_hid_mt_module(hdev);
>> return -ENODEV;
>> }
>>
>> @@ -2107,6 +2134,8 @@ struct hid_device *hid_allocate_device(void)
>> INIT_LIST_HEAD(&hdev->debug_list);
>> sema_init(&hdev->driver_lock, 1);
>>
>> + hdev->request_hid_mt_module = 0;
>> +
>
> Allocated using kzalloc, so no need.
>
>> return hdev;
>> err:
>> put_device(&hdev->dev);
>> @@ -2121,6 +2150,8 @@ static void hid_remove_device(struct hid_device *hdev)
>> hid_debug_unregister(hdev);
>> hdev->status &= ~HID_STAT_ADDED;
>> }
>> + if (hdev->request_hid_mt_module)
>> + hid_flush_request_modules(hdev);
>
> I would put the test inside the flush function instead, to restrict
> the use of the bare variables.
>
>> }
>>
>> /**
>> diff --git a/include/linux/hid.h b/include/linux/hid.h
>> index 3a95da6..0058ca9 100644
>> --- a/include/linux/hid.h
>> +++ b/include/linux/hid.h
>> @@ -538,6 +538,14 @@ struct hid_device { /* device report descriptor */
>> struct dentry *debug_events;
>> struct list_head debug_list;
>> wait_queue_head_t debug_wait;
>> +
>> + /* This is a temporary fix to make hid-multitouch loadable from
>> + * the kernel before we come up with more robust solution
>> + * (with userspace involvement).
>> + * In case we detect a multitouch device through the parsing of
>> + * hid-core, we request for hid-multitouch to be loaded. */
>> + struct work_struct request_hid_mt_module_wk;
>> + bool request_hid_mt_module;
>
> This increases memory per hid device, which is not so nice. A static
> declaration in the core module ought to suffice. Probably needs
> additional locking as well.
>
>> };
>>
>> static inline void *hid_get_drvdata(struct hid_device *hdev)
>> --
>> 1.7.7.6
>>
>
> Thanks,
> Henrik
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