From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754850AbaDWMbt (ORCPT ); Wed, 23 Apr 2014 08:31:49 -0400 Received: from prifuk.cz ([31.31.77.140]:49614 "EHLO smtp.devoid-pointer.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754781AbaDWMbq convert rfc822-to-8bit (ORCPT ); Wed, 23 Apr 2014 08:31:46 -0400 From: Michal =?ISO-8859-1?Q?Mal=FD?= To: Oliver Neukum Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, dmitry.torokhov@gmail.com, jkosina@suse.cz, elias.vds@gmail.com, anssi.hannula@iki.fi, simon@mungewell.org Subject: Re: [PATCH v2 11/24] input: Port hid-holtekff to ff-memless-next Date: Wed, 23 Apr 2014 14:31:42 +0200 Message-ID: <1592278.pD8vu465lA@sigyn> User-Agent: KMail/4.13 (Linux/3.14.1-1-my-rd; KDE/4.13.0; x86_64; ; ) In-Reply-To: <1398255470.32091.3.camel@linux-fkkt.site> References: <1398175209-9565-1-git-send-email-madcatxster@devoid-pointer.net> <1398175209-9565-12-git-send-email-madcatxster@devoid-pointer.net> <1398255470.32091.3.camel@linux-fkkt.site> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="iso-8859-1" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 23 of April 2014 14:17:50 Oliver Neukum wrote: > On Tue, 2014-04-22 at 15:59 +0200, Michal Malư wrote: > > static int holtekff_play(struct input_dev *dev, void *data, > > > > - struct ff_effect *effect) > > + const struct mlnx_effect_command *command) > > > > { > > > > struct hid_device *hid = input_get_drvdata(dev); > > struct holtekff_device *holtekff = data; > > > > + const struct mlnx_rumble_force *rumble_force = > > &command->u.rumble_force; > > > > int left, right; > > /* effect type 1, length 65535 msec */ > > u8 buf[HOLTEKFF_MSG_LENGTH] = > > > > { 0x01, 0x01, 0xff, 0xff, 0x10, 0xe0, 0x00 }; > > On the kernel stack. > > > - left = effect->u.rumble.strong_magnitude; > > - right = effect->u.rumble.weak_magnitude; > > - dbg_hid("called with 0x%04x 0x%04x\n", left, right); > > + switch (command->cmd) { > > + case MLNX_START_RUMBLE: > > + left = rumble_force->strong; > > + right = rumble_force->weak; > > + dbg_hid("called with 0x%04x 0x%04x\n", left, right); > > > > - if (!left && !right) { > > - holtekff_send(holtekff, hid, stop_all6); > > - return 0; > > - } > > + if (!left && !right) { > > + holtekff_send(holtekff, hid, stop_all6); > > + return 0; > > + } > > > > - if (left) > > - buf[1] |= 0x80; > > - if (right) > > - buf[1] |= 0x40; > > + if (left) > > + buf[1] |= 0x80; > > + if (right) > > + buf[1] |= 0x40; > > > > - /* The device takes a single magnitude, so we just sum them > > up. */ > > - buf[6] = min(0xf, (left >> 12) + (right >> 12)); > > + /* The device takes a single magnitude, so we just sum > > them up. */ > > + buf[6] = min(0xf, (left >> 12) + (right >> 12)); > > > > - holtekff_send(holtekff, hid, buf); > > - holtekff_send(holtekff, hid, start_effect_1); > > + holtekff_send(holtekff, hid, buf); > > + holtekff_send(holtekff, hid, start_effect_1); > > + return 0; > > + case MLNX_STOP_RUMBLE: > > + holtekff_send(holtekff, hid, stop_all6); > > + return 0; > > + default: > > + return -EINVAL; > > + } > > > > return 0; > > > > } > > This looks very much like doing DMA on the kernel stack. > That is very strictly forbidden. The bug is also in the current > code, but would you care to fix it up? Okay, I'll look into it. Michal