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Date: Wed, 22 Oct 2014 12:51:17 +0200
From: Pali Rohár <pali.rohar@...il.com>
To: Darren Hart <dvhart@...radead.org>
Cc: Matthew Garrett <mjg59@...f.ucam.org>,
platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
Gabriele Mazzotta <gabriele.mzt@...il.com>
Subject: Re: [PATCH] dell-wmi: Update code for processing WMI events
On Tuesday 21 October 2014 23:32:12 Darren Hart wrote:
> On Tue, Oct 21, 2014 at 12:15:24AM +0200, Pali Rohár wrote:
> > WMI buffer can contains more events. First value in buffer
> > is length of event followed by data of specified length.
> > After that is next length and next data. When length is
> > zero then there is no more events in bufffer.
> >
> > This patch adds support for processing all events in buffer
> > (not only first) and parse more event types (not only
> > hotkey events). Because of variable length of events
> > sometimes BIOS fills more hotkeys (or other values) into
> > single WMI event. In this case this patch process also
> > these multiple hotkeys (and not only first one).
> >
> > Some event types are just ignored because kernel is not
> > interested for them (e.g. NIC Link status, battery unplug,
> > ...).
> >
> > This patch is based on DSDT table from Dell Latitude E6440.
> > Code should be backward compatible so will process other
> > events of old types same as before this patch.
> >
> > This patch also fixes problem when in kernel log are written
> > messages about unknown WMI events. Now all know events are
> > parsed and those which are not interesting for kernel are
> > dropped without unknown message.
>
> This should probably be done in a separate patch.
>
It is not possible, because my patch rewrite code for handling
events. Kernel does not print "unknown event" messages when it
parse WMI event and understand specified part.
> > Signed-off-by: Pali Rohár <pali.rohar@...il.com>
> > Tested-by: Pali Rohár <pali.rohar@...il.com>
>
> Well yes, I should hope so ;-)
>
> > ---
> >
> > drivers/platform/x86/dell-wmi.c | 157
> > +++++++++++++++++++++++++++++++-------- 1 file changed,
> > 127 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/platform/x86/dell-wmi.c
> > b/drivers/platform/x86/dell-wmi.c index 25721bf..3d15949
> > 100644
> > --- a/drivers/platform/x86/dell-wmi.c
> > +++ b/drivers/platform/x86/dell-wmi.c
> > @@ -145,11 +145,35 @@ static const u16
> > bios_to_linux_keycode[256] __initconst = {
> >
> > static struct input_dev *dell_wmi_input_dev;
> >
> > +static void dell_wmi_process_key(int reported_key)
> > +{
> > + const struct key_entry *key;
> > +
> > + key =
> > sparse_keymap_entry_from_scancode(dell_wmi_input_dev,
> > + reported_key);
> > + if (!key) {
> > + pr_info("Unknown key %x pressed\n", reported_key);
> > + return;
> > + }
> > +
> > + pr_debug("Key %x pressed\n", reported_key);
> > +
> > + /* Don't report brightness notifications that will also
> > come via ACPI */ + if ((key->keycode == KEY_BRIGHTNESSUP ||
> > + key->keycode == KEY_BRIGHTNESSDOWN) && acpi_video)
> > + return;
> > +
> > + sparse_keymap_report_entry(dell_wmi_input_dev, key, 1,
> > true); +}
> > +
> >
> > static void dell_wmi_notify(u32 value, void *context)
> > {
> >
> > struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL
> > }; union acpi_object *obj;
> > acpi_status status;
> >
> > + acpi_size buffer_size;
> > + u16 *buffer_entry, *buffer_end;
> > + int len, i;
> >
> > status = wmi_get_event_data(value, &response);
> > if (status != AE_OK) {
> >
> > @@ -158,44 +182,117 @@ static void dell_wmi_notify(u32
> > value, void *context)
> >
> > }
> >
> > obj = (union acpi_object *)response.pointer;
> >
> > + if (!obj) {
> > + pr_info("no response\n");
> > + return;
> > + }
>
> If you intend to print this, it should probably be a bit more
> informative. Is "info" the right level here? I would imagine
> either WARN if this was a bad thing, or DEBUG if this is more
> for debugging the driver.
>
So what you (or somebody else) prefer? warn or debug?
> > - if (obj && obj->type == ACPI_TYPE_BUFFER) {
> > - const struct key_entry *key;
> > - int reported_key;
> > - u16 *buffer_entry = (u16 *)obj->buffer.pointer;
> > - int buffer_size = obj->buffer.length/2;
> > -
> > - if (buffer_size >= 2 && dell_new_hk_type &&
> > buffer_entry[1] != 0x10) { - pr_info("Received
unknown
> > WMI event (0x%x)\n",
> > - buffer_entry[1]);
> > - kfree(obj);
> > - return;
> > - }
> > + if (obj->type != ACPI_TYPE_BUFFER) {
> > + pr_info("bad response type %x\n", obj->type);
> > + kfree(obj);
> > + return;
> > + }
> > +
> > + pr_debug("Received WMI event (%*ph)\n",
> > + obj->buffer.length, obj->buffer.pointer);
> >
> > - if (buffer_size >= 3 && (dell_new_hk_type ||
> > buffer_entry[1] == 0x0)) - reported_key =
> > (int)buffer_entry[2];
> > + buffer_entry = (u16 *)obj->buffer.pointer;
> > + buffer_size = obj->buffer.length/2;
> > +
> > + if (!dell_new_hk_type) {
> > + if (buffer_size >= 3 && buffer_entry[1] == 0x0)
> > + dell_wmi_process_key(buffer_entry[2]);
> >
> > else if (buffer_size >= 2)
> >
> > - reported_key = (int)buffer_entry[1] & 0xffff;
> > - else {
> > + dell_wmi_process_key(buffer_entry[1]);
>
> Why can we drop the 0xffff mask now?
>
Because it is useless (or correct me if not!). Variable
buffer_entry has type u16* so operation "AND 0xFFFF" on 16bit
integer do nothing.
> > + else
> >
> > pr_info("Received unknown WMI event\n");
> >
> > - kfree(obj);
> > - return;
> > + kfree(obj);
> > + return;
> > + }
> > +
> > + buffer_end = buffer_entry + buffer_size;
> > +
> > + while (buffer_entry < buffer_end) {
> > +
> > + len = buffer_entry[0];
> > + if (len == 0)
> > + break;
> > +
> > + len++;
> > +
>
> Why increment len here? Are you trying to avoid a "len + 1" in
> the comparisons below? If so, is using "len * 2" in the debug
> message below correct? Please clarify.
>
in buffer_entry[0] (16 bit integer) is stored length of event (in
16bit units) without first (length) value. And "%*ph" takes size
in bytes (u8). So length in bytes (u8) units is 2 * length in u16
units.
> > + if (buffer_entry+len > buffer_end) {
>
> See coding style documentation on operators. Please run
> patches through checkpatch.
>
checkpatch.pl does not show any problem for these lines.
> > + pr_info("Invalid length of WMI event\n");
>
> info doesn't see correct here either.
>
debug or warn?
> > + break;
> >
> > }
> >
> > - key =
> > sparse_keymap_entry_from_scancode(dell_wmi_input_dev,
> > - reported_key);
> > - if (!key) {
> > - pr_info("Unknown key %x pressed\n", reported_key);
> > - } else if ((key->keycode == KEY_BRIGHTNESSUP ||
> > - key->keycode == KEY_BRIGHTNESSDOWN) &&
acpi_video) {
> > - /* Don't report brightness notifications that will
also
> > - * come via ACPI */
> > - ;
> > - } else {
> > - sparse_keymap_report_entry(dell_wmi_input_dev,
key,
> > - 1, true);
> > + pr_debug("Process buffer (%*ph)\n", len*2,
buffer_entry);
> > +
> > + switch (buffer_entry[1]) {
> > + case 0x00:
> > + for (i = 2; i < len; ++i) {
> > + switch (buffer_entry[i]) {
> > + case 0xe043:
> > + /* NIC Link is Up */
> > + pr_debug("NIC Link is Up\n");
> > + break;
> > + case 0xe044:
> > + /* NIC Link is Down */
> > + pr_debug("NIC Link is Down\n");
> > + break;
> > + case 0xe045:
> > + /* Unknown event but defined in DSDT */
> > + default:
> > + /* Unknown event */
> > + pr_info("Unknown WMI event type 0x00: "
> > + "0x%x\n", (int)buffer_entry[i]);
> > + break;
> > + }
> > + }
> > + break;
> > + case 0x10:
> > + /* Keys pressed */
> > + for (i = 2; i < len; ++i)
> > + dell_wmi_process_key(buffer_entry[i]);
> > + break;
> > + case 0x11:
> > + for (i = 2; i < len; ++i) {
> > + switch (buffer_entry[i]) {
> > + case 0xfff0:
> > + /* Battery unplugged */
> > + pr_debug("Battery unplugged\n");
> > + break;
> > + case 0xfff1:
> > + /* Battery inserted */
> > + pr_debug("Battery inserted\n");
> > + break;
> > + case 0x01e1:
> > + case 0x02ea:
> > + case 0x02eb:
> > + case 0x02ec:
> > + case 0x02f6:
> > + /* Keyboard backlight level changed */
> > + pr_debug("Keyboard backlight level "
> > + "changed\n");
> > + break;
> > + default:
> > + /* Unknown event */
> > + pr_info("Unknown WMI event type 0x11: "
> > + "0x%x\n", (int)buffer_entry[i]);
> > + break;
> > + }
> > + }
> > + break;
> > + default:
> > + /* Unknown event */
> > + pr_info("Unknown WMI event type 0x%x\n",
> > + (int)buffer_entry[1]);
> > + break;
> >
> > }
> >
> > +
> > + buffer_entry += len;
> > +
> >
> > }
> >
> > +
> >
> > kfree(obj);
> >
> > }
--
Pali Rohár
pali.rohar@...il.com
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