Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262388AbUFEHtX (ORCPT ); Sat, 5 Jun 2004 03:49:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263862AbUFEHtX (ORCPT ); Sat, 5 Jun 2004 03:49:23 -0400 Received: from smtp814.mail.sc5.yahoo.com ([66.163.170.84]:4512 "HELO smtp814.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S262388AbUFEHtF (ORCPT ); Sat, 5 Jun 2004 03:49:05 -0400 From: Dmitry Torokhov To: linux-kernel@vger.kernel.org Subject: [PATCH 2.6] Mousedev - better button handling under load Date: Sat, 5 Jun 2004 02:49:00 -0500 User-Agent: KMail/1.6.2 Cc: Andrew Morton , Vojtech Pavlik MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Message-Id: <200406050249.02523.dtor_core@ameritech.net> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9050 Lines: 312 Hi, Currently mousedev combines all hardware motion data that arrivers since last time userspace read data into one cooked PS/2 packet. The problem is that under heavy or even moderate load, when userspace can't read data quickly enough, we start loosing valuable data which manifests in: - ignoring buton presses as by the time userspace gets to read the data button has already been released; - click starts in wrong place - by the time userspace got aroungd and read the packet mouse moved half way across the screen. The patch below corrects the issue - it will start accumulating new packet every time userspace is behind and button set changes. Size of the buffer is 16 packets, i.e. up to 8 pairs of press/release events which should be more than enough. The patch is against Vojtech's tree and shuld apply to -mm. I also have cumulative mousedev patch done against 2.6.7-pre2 at: http://www.geocities.com/dt_or/input/misc/mousedev-2.6.7-rc2-cumulative.patch.gz -- Dmitry =================================================================== ChangeSet@1.1828, 2004-06-05 01:05:50-05:00, dtor_core@ameritech.net Input: mousedev - better handle button presses when under load Signed-off-by: Dmitry Torokhov mousedev.c | 152 +++++++++++++++++++++++++++++++++++++++++-------------------- 1 files changed, 104 insertions(+), 48 deletions(-) =================================================================== diff -Nru a/drivers/input/mousedev.c b/drivers/input/mousedev.c --- a/drivers/input/mousedev.c 2004-06-05 02:08:31 -05:00 +++ b/drivers/input/mousedev.c 2004-06-05 02:08:31 -05:00 @@ -50,6 +50,7 @@ struct mousedev_motion { int dx, dy, dz; + unsigned long buttons; }; struct mousedev { @@ -62,21 +63,31 @@ struct input_handle handle; struct mousedev_motion packet; - unsigned long buttons; unsigned int pkt_count; int old_x[4], old_y[4]; unsigned int touch; }; +enum mousedev_emul { + MOUSEDEV_EMUL_PS2, + MOUSEDEV_EMUL_IMPS, + MOUSEDEV_EMUL_EXPS +} __attribute__ ((packed)); + +#define PACKET_QUEUE_LEN 16 struct mousedev_list { struct fasync_struct *fasync; struct mousedev *mousedev; struct list_head node; - int dx, dy, dz; - unsigned long buttons; + + struct mousedev_motion packets[PACKET_QUEUE_LEN]; + unsigned int head, tail; + spinlock_t packet_lock; + signed char ps2[6]; unsigned char ready, buffer, bufsiz; - unsigned char mode, imexseq, impsseq; + unsigned char imexseq, impsseq; + enum mousedev_emul mode; }; #define MOUSEDEV_SEQ_LEN 6 @@ -165,24 +176,40 @@ } if (value) { - set_bit(index, &mousedev->buttons); - set_bit(index, &mousedev_mix.buttons); + set_bit(index, &mousedev->packet.buttons); + set_bit(index, &mousedev_mix.packet.buttons); } else { - clear_bit(index, &mousedev->buttons); - clear_bit(index, &mousedev_mix.buttons); + clear_bit(index, &mousedev->packet.buttons); + clear_bit(index, &mousedev_mix.packet.buttons); } } static void mousedev_notify_readers(struct mousedev *mousedev, struct mousedev_motion *packet) { struct mousedev_list *list; + struct mousedev_motion *p; + unsigned long flags; list_for_each_entry(list, &mousedev->list, node) { - list->dx += packet->dx; - list->dy += packet->dy; - list->dz += packet->dz; - list->buttons = mousedev->buttons; + spin_lock_irqsave(&list->packet_lock, flags); + + p = &list->packets[list->head]; + if (list->ready && p->buttons != packet->buttons) { + unsigned int new_head = (list->head + 1) % PACKET_QUEUE_LEN; + if (new_head != list->tail) { + p = &list->packets[list->head = new_head]; + memset(p, 0, sizeof(struct mousedev_motion)); + } + } + + p->dx += packet->dx; + p->dy += packet->dy; + p->dz += packet->dz; + p->buttons = mousedev->packet.buttons; + list->ready = 1; + + spin_unlock_irqrestore(&list->packet_lock, flags); kill_fasync(&list->fasync, SIGIO, POLL_IN); } @@ -237,7 +264,7 @@ mousedev_notify_readers(mousedev, &mousedev->packet); mousedev_notify_readers(&mousedev_mix, &mousedev->packet); - memset(&mousedev->packet, 0, sizeof(struct mousedev_motion)); + mousedev->packet.dx = mousedev->packet.dy = mousedev->packet.dz = 0; } break; } @@ -322,6 +349,7 @@ return -ENOMEM; memset(list, 0, sizeof(struct mousedev_list)); + spin_lock_init(&list->packet_lock); list->mousedev = mousedev_table[i]; list_add_tail(&list->node, &mousedev_table[i]->list); file->private_data = list; @@ -341,32 +369,56 @@ return 0; } -static void mousedev_packet(struct mousedev_list *list, unsigned char off) +static inline int mousedev_limit_delta(int delta, int limit) { - list->ps2[off] = 0x08 | ((list->dx < 0) << 4) | ((list->dy < 0) << 5) | (list->buttons & 0x07); - list->ps2[off + 1] = (list->dx > 127 ? 127 : (list->dx < -127 ? -127 : list->dx)); - list->ps2[off + 2] = (list->dy > 127 ? 127 : (list->dy < -127 ? -127 : list->dy)); - list->dx -= list->ps2[off + 1]; - list->dy -= list->ps2[off + 2]; - list->bufsiz = off + 3; - - if (list->mode == 2) { - list->ps2[off + 3] = (list->dz > 7 ? 7 : (list->dz < -7 ? -7 : list->dz)); - list->dz -= list->ps2[off + 3]; - list->ps2[off + 3] = (list->ps2[off + 3] & 0x0f) | ((list->buttons & 0x18) << 1); - list->bufsiz++; - } else { - list->ps2[off] |= ((list->buttons & 0x10) >> 3) | ((list->buttons & 0x08) >> 1); + return delta > limit ? limit : (delta < -limit ? -limit : delta); +} + +static void mousedev_packet(struct mousedev_list *list, signed char *ps2_data) +{ + struct mousedev_motion *p; + unsigned long flags; + + spin_lock_irqsave(&list->packet_lock, flags); + p = &list->packets[list->tail]; + + ps2_data[0] = 0x08 | ((p->dx < 0) << 4) | ((p->dy < 0) << 5) | (p->buttons & 0x07); + ps2_data[1] = mousedev_limit_delta(p->dx, 127); + ps2_data[2] = mousedev_limit_delta(p->dy, 127); + p->dx -= ps2_data[1]; + p->dy -= ps2_data[2]; + + switch (list->mode) { + case MOUSEDEV_EMUL_EXPS: + ps2_data[3] = mousedev_limit_delta(p->dz, 127); + p->dz -= ps2_data[3]; + ps2_data[3] = (ps2_data[3] & 0x0f) | ((p->buttons & 0x18) << 1); + list->bufsiz = 4; + break; + + case MOUSEDEV_EMUL_IMPS: + ps2_data[0] |= ((p->buttons & 0x10) >> 3) | ((p->buttons & 0x08) >> 1); + ps2_data[3] = mousedev_limit_delta(p->dz, 127); + p->dz -= ps2_data[3]; + list->bufsiz = 4; + break; + + case MOUSEDEV_EMUL_PS2: + default: + ps2_data[0] |= ((p->buttons & 0x10) >> 3) | ((p->buttons & 0x08) >> 1); + p->dz = 0; + list->bufsiz = 3; + break; } - if (list->mode == 1) { - list->ps2[off + 3] = (list->dz > 127 ? 127 : (list->dz < -127 ? -127 : list->dz)); - list->dz -= list->ps2[off + 3]; - list->bufsiz++; + if (!p->dx && !p->dy && !p->dz) { + if (list->tail != list->head) + list->tail = (list->tail + 1) % PACKET_QUEUE_LEN; + if (list->tail == list->head) + list->ready = 0; } - if (!list->dx && !list->dy && (!list->mode || !list->dz)) list->ready = 0; - list->buffer = list->bufsiz; + spin_unlock_irqrestore(&list->packet_lock, flags); } @@ -384,31 +436,31 @@ if (c == mousedev_imex_seq[list->imexseq]) { if (++list->imexseq == MOUSEDEV_SEQ_LEN) { list->imexseq = 0; - list->mode = 2; + list->mode = MOUSEDEV_EMUL_EXPS; } } else list->imexseq = 0; if (c == mousedev_imps_seq[list->impsseq]) { if (++list->impsseq == MOUSEDEV_SEQ_LEN) { list->impsseq = 0; - list->mode = 1; + list->mode = MOUSEDEV_EMUL_IMPS; } } else list->impsseq = 0; list->ps2[0] = 0xfa; - list->bufsiz = 1; switch (c) { case 0xeb: /* Poll */ - mousedev_packet(list, 1); + mousedev_packet(list, &list->ps2[1]); + list->bufsiz++; /* account for leading ACK */ break; case 0xf2: /* Get ID */ switch (list->mode) { - case 0: list->ps2[1] = 0; break; - case 1: list->ps2[1] = 3; break; - case 2: list->ps2[1] = 4; break; + case MOUSEDEV_EMUL_PS2: list->ps2[1] = 0; break; + case MOUSEDEV_EMUL_IMPS: list->ps2[1] = 3; break; + case MOUSEDEV_EMUL_EXPS: list->ps2[1] = 4; break; } list->bufsiz = 2; break; @@ -419,13 +471,15 @@ break; case 0xff: /* Reset */ - list->impsseq = 0; - list->imexseq = 0; - list->mode = 0; - list->ps2[1] = 0xaa; - list->ps2[2] = 0x00; + list->impsseq = list->imexseq = 0; + list->mode = MOUSEDEV_EMUL_PS2; + list->ps2[1] = 0xaa; list->ps2[2] = 0x00; list->bufsiz = 3; break; + + default: + list->bufsiz = 1; + break; } list->buffer = list->bufsiz; @@ -451,8 +505,10 @@ if (retval) return retval; - if (!list->buffer && list->ready) - mousedev_packet(list, 0); + if (!list->buffer && list->ready) { + mousedev_packet(list, list->ps2); + list->buffer = list->bufsiz; + } if (count > list->buffer) count = list->buffer; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/