| Message ID | 20200514224929.GA1026616@jelly (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Jiri Kosina |
| Headers | show |
| Series | [RESEND] HID: input: do not run GET_REPORT unless there's a Resolution Multiplier | expand |
Hi Peter, On Fri, May 15, 2020 at 12:49 AM Peter Hutterer <peter.hutterer@who-t.net> wrote: > > hid-multitouch currently runs GET_REPORT for Contact Max and again to > retrieve the Win8 blob. If both are within the same report, the > Resolution Multiplier code calls GET_FEATURE again and this time, > possibly due to timing, it causes the ILITEK-TP device interpret the > GET_FEATURE as an instruction to change the mode and effectively stop > the device from functioning as expected. > > Notably: the device doesn't even have a Resolution Multiplier so it > shouldn't be affected by any of this at all. > > Fix this by making sure we only execute GET_REPORT if there is > a Resolution Multiplier in the respective report. > > Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net> > Tested-by: Wen He <wen.he_1@nxp.com> > --- > Same patch as before, but this time with diff.noprefix set to false again. > Too bad that setting messes up format-patch :( Apologies for the broken > one. Thanks for the quick respin. I was about to apply it, and then I realized that something was off (see inlined) > > drivers/hid/hid-input.c | 22 ++++++++++++---------- > 1 file changed, 12 insertions(+), 10 deletions(-) > > diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c > index dea9cc65bf80..a54824d451bf 100644 > --- a/drivers/hid/hid-input.c > +++ b/drivers/hid/hid-input.c > @@ -1560,21 +1560,12 @@ static bool __hidinput_change_resolution_multipliers(struct hid_device *hid, > { > struct hid_usage *usage; > bool update_needed = false; > + bool get_report_completed = false; > int i, j; > > if (report->maxfield == 0) > return false; > > - /* > - * If we have more than one feature within this report we > - * need to fill in the bits from the others before we can > - * overwrite the ones for the Resolution Multiplier. > - */ > - if (report->maxfield > 1) { > - hid_hw_request(hid, report, HID_REQ_GET_REPORT); > - hid_hw_wait(hid); > - } > - > for (i = 0; i < report->maxfield; i++) { > __s32 value = use_logical_max ? > report->field[i]->logical_maximum : > @@ -1593,6 +1584,17 @@ static bool __hidinput_change_resolution_multipliers(struct hid_device *hid, > if (usage->hid != HID_GD_RESOLUTION_MULTIPLIER) > continue; > > + /* > + * If we have more than one feature within this report we > + * need to fill in the bits from the others before we can > + * overwrite the ones for the Resolution Multiplier. > + */ > + if (!get_report_completed && report->maxfield > 1) { > + hid_hw_request(hid, report, HID_REQ_GET_REPORT); I think here we said that the reading of this particular feature was mandatory by Microsoft, but what if a device doesn't like it. I wonder if we should not guard this against HID_QUIRK_NO_INIT_REPORTS too, in the event we need to quirk a particular device. (BTW, I prefer this version compared to the first draft you sent me :-P ) Cheers, Benjamin > + hid_hw_wait(hid); > + get_report_completed = true; > + } > + > report->field[i]->value[j] = value; > update_needed = true; > } > -- > 2.26.2 >
On Fri, May 15, 2020 at 09:48:18AM +0200, Benjamin Tissoires wrote: > Hi Peter, > > On Fri, May 15, 2020 at 12:49 AM Peter Hutterer > <peter.hutterer@who-t.net> wrote: > > > > hid-multitouch currently runs GET_REPORT for Contact Max and again to > > retrieve the Win8 blob. If both are within the same report, the > > Resolution Multiplier code calls GET_FEATURE again and this time, > > possibly due to timing, it causes the ILITEK-TP device interpret the > > GET_FEATURE as an instruction to change the mode and effectively stop > > the device from functioning as expected. > > > > Notably: the device doesn't even have a Resolution Multiplier so it > > shouldn't be affected by any of this at all. > > > > Fix this by making sure we only execute GET_REPORT if there is > > a Resolution Multiplier in the respective report. > > > > Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net> > > Tested-by: Wen He <wen.he_1@nxp.com> > > --- > > Same patch as before, but this time with diff.noprefix set to false again. > > Too bad that setting messes up format-patch :( Apologies for the broken > > one. > > Thanks for the quick respin. I was about to apply it, and then I > realized that something was off (see inlined) > > > > > drivers/hid/hid-input.c | 22 ++++++++++++---------- > > 1 file changed, 12 insertions(+), 10 deletions(-) > > > > diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c > > index dea9cc65bf80..a54824d451bf 100644 > > --- a/drivers/hid/hid-input.c > > +++ b/drivers/hid/hid-input.c > > @@ -1560,21 +1560,12 @@ static bool __hidinput_change_resolution_multipliers(struct hid_device *hid, > > { > > struct hid_usage *usage; > > bool update_needed = false; > > + bool get_report_completed = false; > > int i, j; > > > > if (report->maxfield == 0) > > return false; > > > > - /* > > - * If we have more than one feature within this report we > > - * need to fill in the bits from the others before we can > > - * overwrite the ones for the Resolution Multiplier. > > - */ > > - if (report->maxfield > 1) { > > - hid_hw_request(hid, report, HID_REQ_GET_REPORT); > > - hid_hw_wait(hid); > > - } > > - > > for (i = 0; i < report->maxfield; i++) { > > __s32 value = use_logical_max ? > > report->field[i]->logical_maximum : > > @@ -1593,6 +1584,17 @@ static bool __hidinput_change_resolution_multipliers(struct hid_device *hid, > > if (usage->hid != HID_GD_RESOLUTION_MULTIPLIER) > > continue; > > > > + /* > > + * If we have more than one feature within this report we > > + * need to fill in the bits from the others before we can > > + * overwrite the ones for the Resolution Multiplier. > > + */ > > + if (!get_report_completed && report->maxfield > 1) { > > + hid_hw_request(hid, report, HID_REQ_GET_REPORT); > > I think here we said that the reading of this particular feature was > mandatory by Microsoft, but what if a device doesn't like it. > I wonder if we should not guard this against HID_QUIRK_NO_INIT_REPORTS > too, in the event we need to quirk a particular device. just to clarify: "I wonder if" means "please add this" here? :) tbh I don't see how a device could function if one cannot read the report with the RM - Windows reads and sets it unconditionally so that device would break under Windows. Which, presumably, is motivation enough for a vendor to fix it. I'm not even sure there are devices where this is ever triggered now, having two unrelated features in the same report seems a bit of a niche case. We can easily add the check but whether it'll ever be needed is doubtful. Cheers, Peter
diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index dea9cc65bf80..a54824d451bf 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -1560,21 +1560,12 @@ static bool __hidinput_change_resolution_multipliers(struct hid_device *hid, { struct hid_usage *usage; bool update_needed = false; + bool get_report_completed = false; int i, j; if (report->maxfield == 0) return false; - /* - * If we have more than one feature within this report we - * need to fill in the bits from the others before we can - * overwrite the ones for the Resolution Multiplier. - */ - if (report->maxfield > 1) { - hid_hw_request(hid, report, HID_REQ_GET_REPORT); - hid_hw_wait(hid); - } - for (i = 0; i < report->maxfield; i++) { __s32 value = use_logical_max ? report->field[i]->logical_maximum : @@ -1593,6 +1584,17 @@ static bool __hidinput_change_resolution_multipliers(struct hid_device *hid, if (usage->hid != HID_GD_RESOLUTION_MULTIPLIER) continue; + /* + * If we have more than one feature within this report we + * need to fill in the bits from the others before we can + * overwrite the ones for the Resolution Multiplier. + */ + if (!get_report_completed && report->maxfield > 1) { + hid_hw_request(hid, report, HID_REQ_GET_REPORT); + hid_hw_wait(hid); + get_report_completed = true; + } + report->field[i]->value[j] = value; update_needed = true; }