Re: [PATCHv2 001/002] usbhid: Fix initialisation for the Microsoft Sidewinder Force Feedback Pro 2 joystick

2015-01-21 Thread Jim Keir

Hi,

Thanks for the feedback. I've included a replacement patch here for the 
first issue, and will send a separate message with a patch for the third 
issue. I've removed the second as per Alan's request. This diff is 
against the latest version of the hid branch rather than the 3.13 branch 
I was using before. Apologies for the mistakes, I'm still feeling my way 
around here.


---

Allow the Microsoft Sidewinder Force Feedback 2 joystick to perform the 
required communication with the device during initialisation.


Signed-off-by: Jim Keir jimk...@oracledbadirect.com

---

diff --git a/drivers/hid/usbhid/hid-pidff.c b/drivers/hid/usbhid/hid-pidff.c
index 10b6167..1b3fa70 100644
--- a/drivers/hid/usbhid/hid-pidff.c
+++ b/drivers/hid/usbhid/hid-pidff.c
@@ -1252,6 +1258,8 @@ int hid_pidff_init(struct hid_device *hid)

 pidff-hid = hid;

+hid_device_io_start(hid);
+
 pidff_find_reports(hid, HID_OUTPUT_REPORT, pidff);
 pidff_find_reports(hid, HID_FEATURE_REPORT, pidff);

@@ -1315,9 +1323,13 @@ int hid_pidff_init(struct hid_device *hid)

 hid_info(dev, Force feedback for USB HID PID devices by Anssi 
Hannula anssi.hann...@gmail.com\n);


+hid_device_io_stop(hid);
+
 return 0;

  fail:
+hid_device_io_stop(hid);
+
 kfree(pidff);
 return error;
 }

---

On 20/01/2015 14:09, Benjamin Tissoires wrote:

Hi,

Jim, in addition to what Alan said, here are some comments that I
would like to be fixed in the v2.

On Sun, Jan 18, 2015 at 11:07 AM, Jim Keir jimk...@oracledbadirect.com wrote:

From: Jim Keir jimk...@yahoo.co.uk
Signed-off-by: Jim Keir jimk...@yahoo.co.uk


The Signed-off-by line is generally at the end of the commit message.
This way, if someone else adds new changes to the patch, we can trace
which modifications belongs to which.


Currently the SWFF2 driver fails during initialisation, making the force
capability of the joystick unusable. Further, there is a long-standing
bug in the same driver where commands to update force parameters are
addressed to the last-created force effect instead of the specified one,
making it impossible to modify effects after their creation.

Three bugs are addressed:

1) The FF2 driver (usbhid/hid-pidff.c) sends commands to the stick
during ff_init. However, this is called inside a block where
driver_input_lock is locked, so the results of these initial commands
are discarded. This one is the killer, without this nothing else works.

ff_init issues commands using hid_hw_request. This eventually goes to
hid_input_report, which returns -EBUSY because driver_input_lock is
locked. The change is to delay the ff_init call in hid-core.c until
after this lock has been released.

2) The usbhid driver ignores an endpoint stall when sending control
commands, causing the first few commands of the hid-pidff.c
initialisation to get lost.

usbhid/hid-core.c has been modified by copying lines into hid_ctrl
from the hid_irq_in function in the same file.

3) The FF2 driver (usbhid/hid-pidff.c) does not set the effect ID when
uploading an effect. The result is that the initial upload works but
subsequent uploads to modify effect parameters are all directed at the
last-created effect.


Fully agree that you should split the commit in 3 if there are 3
issues (and to the rest Alan said also, but this is the most important
I think).



The targeted effect ID must be passed back to the device when effect
parameters are changed. This is done at the start of
pidff_set_condition_report, pidff_set_periodic_report etc. based on
the value of pidff-block_load[PID_EFFECT_BLOCK_INDEX].value[0].
However, this value is only ever set during pidff_request_effect_upload.
The result is stored in pidff-pid_id[effect-id] at the end of
pid_upload_effect, for later use. However, if an effect is modified and
re-sent then this identifier is not being copied back from
pidff-pid_id[effect-id] before sending the command to the device. The
fix is to do this at the start of pidff_upload_effect.

This patch taken against kernel 3.13.0

---

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 905e40a..a608ee6 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1546,9 +1546,8 @@ int hid_connect(struct hid_device *hdev, unsigned int
connect_mask)

On my local tree, hid_connect is at 1562. Is your patch based on the
for-next branch of the HID tree?
https://git.kernel.org/cgit/linux/kernel/git/jikos/hid.git



  return -ENODEV;
  }

-if ((hdev-claimed  HID_CLAIMED_INPUT) 
-(connect_mask  HID_CONNECT_FF)  hdev-ff_init)
-hdev-ff_init(hdev);
+/* Removed ff_init() call from here. It does device I/O but this
+ * is blocked because driver_input_lock is currently locked. */

Please don't. If the feedback driver needs to have access to the IO
earlier, it needs to call hid_device_io_start() (and eventually
hid_device_io_stop() if some other initialization are required).


  len = 0;
  if (hdev-claimed  

Re: [PATCHv2 001/002] usbhid: Fix initialisation for the Microsoft Sidewinder Force Feedback Pro 2 joystick

2015-01-21 Thread Benjamin Tissoires
HI Jim,

On Wed, Jan 21, 2015 at 9:29 AM, Jim Keir jimk...@oracledbadirect.com wrote:
 Hi,

 Thanks for the feedback. I've included a replacement patch here for the
 first issue, and will send a separate message with a patch for the third
 issue. I've removed the second as per Alan's request. This diff is against
 the latest version of the hid branch rather than the 3.13 branch I was using
 before. Apologies for the mistakes, I'm still feeling my way around here.

No worries.


 ---

 Allow the Microsoft Sidewinder Force Feedback 2 joystick to perform the
 required communication with the device during initialisation.

Hmm weird, your mailer did not cut this line... It's better to have it
on 2 separate lines for the actual commit message (no more than 72 or
80 columns).


 Signed-off-by: Jim Keir jimk...@oracledbadirect.com

 ---

This time the order of the various elements is nearly good :)

Git consider that the Subject and the first part of the message (until
the first '---') are to be included in the commit (so the commit title
and the commit message). Then, between the first '---' and the first
diff, you can put whatever comments you like. and then a second '---'
terminates the patch (and you can add garbage like thanks, or the list
footer).
Anyway, I am unable to double check what I just said because your
mailer corrupted the patch.
It converted the tabs in spaces and broke the lines when it should not have.

Please resend the two patches using git send-email.

Just use git format-patch. Then edit the file in an editor to add the
greetings and a short difference between v1 and v2 after the first ---
(your explanations before the first --- should be sufficient), then
use git send-email to send it. No need to link the thread with this
mail or the previous thread.


 diff --git a/drivers/hid/usbhid/hid-pidff.c b/drivers/hid/usbhid/hid-pidff.c
 index 10b6167..1b3fa70 100644
 --- a/drivers/hid/usbhid/hid-pidff.c
 +++ b/drivers/hid/usbhid/hid-pidff.c
 @@ -1252,6 +1258,8 @@ int hid_pidff_init(struct hid_device *hid)

  pidff-hid = hid;

 +hid_device_io_start(hid);
 +

I *think* we should be able to move this later a little bit. Not a
biggie however.

  pidff_find_reports(hid, HID_OUTPUT_REPORT, pidff);
  pidff_find_reports(hid, HID_FEATURE_REPORT, pidff);

 @@ -1315,9 +1323,13 @@ int hid_pidff_init(struct hid_device *hid)

  hid_info(dev, Force feedback for USB HID PID devices by Anssi Hannula
 anssi.hann...@gmail.com\n);

 +hid_device_io_stop(hid);
 +
  return 0;

   fail:
 +hid_device_io_stop(hid);
 +

For the record, we need to close the IO when leaving or the whole IO
mutex will be moot.

Cheers,
Benjamin

  kfree(pidff);
  return error;
  }

 ---

 On 20/01/2015 14:09, Benjamin Tissoires wrote:

 Hi,

 Jim, in addition to what Alan said, here are some comments that I
 would like to be fixed in the v2.

 On Sun, Jan 18, 2015 at 11:07 AM, Jim Keir jimk...@oracledbadirect.com
 wrote:

 From: Jim Keir jimk...@yahoo.co.uk
 Signed-off-by: Jim Keir jimk...@yahoo.co.uk

 The Signed-off-by line is generally at the end of the commit message.
 This way, if someone else adds new changes to the patch, we can trace
 which modifications belongs to which.

 Currently the SWFF2 driver fails during initialisation, making the force
 capability of the joystick unusable. Further, there is a long-standing
 bug in the same driver where commands to update force parameters are
 addressed to the last-created force effect instead of the specified one,
 making it impossible to modify effects after their creation.

 Three bugs are addressed:

 1) The FF2 driver (usbhid/hid-pidff.c) sends commands to the stick
 during ff_init. However, this is called inside a block where
 driver_input_lock is locked, so the results of these initial commands
 are discarded. This one is the killer, without this nothing else works.

 ff_init issues commands using hid_hw_request. This eventually goes to
 hid_input_report, which returns -EBUSY because driver_input_lock is
 locked. The change is to delay the ff_init call in hid-core.c until
 after this lock has been released.

 2) The usbhid driver ignores an endpoint stall when sending control
 commands, causing the first few commands of the hid-pidff.c
 initialisation to get lost.

 usbhid/hid-core.c has been modified by copying lines into hid_ctrl
 from the hid_irq_in function in the same file.

 3) The FF2 driver (usbhid/hid-pidff.c) does not set the effect ID when
 uploading an effect. The result is that the initial upload works but
 subsequent uploads to modify effect parameters are all directed at the
 last-created effect.

 Fully agree that you should split the commit in 3 if there are 3
 issues (and to the rest Alan said also, but this is the most important
 I think).


 The targeted effect ID must be passed back to the device when effect
 parameters are changed. This is done at the start of
 pidff_set_condition_report, pidff_set_periodic_report etc. based