From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kyle Evans Subject: Re: [PATCH] hp-wmi: limit hotkey enable Date: Tue, 08 Sep 2015 10:58:47 -0500 Message-ID: <55EF05B7.2020206@gmail.com> References: <1438959360-20901-1-git-send-email-kvans32@gmail.com> <20150828184228.GA64484@vmdeb7> <55E1CF30.10501@gmail.com> <20150906180339.GC90062@vmdeb7> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-io0-f179.google.com ([209.85.223.179]:35055 "EHLO mail-io0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755405AbbIHP6u (ORCPT ); Tue, 8 Sep 2015 11:58:50 -0400 Received: by ioiz6 with SMTP id z6so123231386ioi.2 for ; Tue, 08 Sep 2015 08:58:49 -0700 (PDT) In-Reply-To: <20150906180339.GC90062@vmdeb7> Sender: platform-driver-x86-owner@vger.kernel.org List-ID: To: Darren Hart Cc: platform-driver-x86@vger.kernel.org, Rafael Wysocki On 09/06/2015 01:03 PM, Darren Hart wrote: > On Sat, Aug 29, 2015 at 10:26:40AM -0500, Kyle Evans wrote: >> On 08/28/2015 01:42 PM, Darren Hart wrote: >>> On Fri, Aug 07, 2015 at 09:56:00AM -0500, Kyle Evans wrote: >>>> Do not attempt to initialize hotkeys if the query returns a value. >>>> Furthermore, do not write initialize magic on systems that do not have >>>> feature query 0xb. Fixes Bug #82451. >>>> >>>> Signed-off-by: Kyle Evans >>> >>> Hi Kyle, >>> >>> Please always include the maintainer from MAINTAINERS on Cc when submitting >>> kernel patches. See Documentation/SubmittingPatches. >>> >>> For example: >>> >>> $ scripts/get_maintainer.pl -f drivers/platform/x86/hp-wmi.c >>> Darren Hart (maintainer:X86 PLATFORM DRIVERS) >>> platform-driver-x86@vger.kernel.org (open list:X86 PLATFORM DRIVERS) >>> linux-kernel@vger.kernel.org (open list) >>> >>> This will ensure a more timely response. >>> >>>> --- >>>> drivers/platform/x86/hp-wmi.c | 17 +++++++++++++---- >>>> 1 file changed, 13 insertions(+), 4 deletions(-) >>>> >>>> diff --git a/drivers/platform/x86/hp-wmi.c b/drivers/platform/x86/hp-wmi.c >>>> index 0669731..557650f 100644 >>>> --- a/drivers/platform/x86/hp-wmi.c >>>> +++ b/drivers/platform/x86/hp-wmi.c >>>> @@ -54,6 +54,7 @@ MODULE_ALIAS("wmi:5FB7F034-2C63-45e9-BE91-3D44E2C707E4"); >>>> #define HPWMI_HARDWARE_QUERY 0x4 >>>> #define HPWMI_WIRELESS_QUERY 0x5 >>>> #define HPWMI_BIOS_QUERY 0x9 >>>> +#define HPWMI_FEATURE2_QUERY 0xb >>>> #define HPWMI_HOTKEY_QUERY 0xc >>>> #define HPWMI_FEATURE_QUERY 0xd >>>> #define HPWMI_WIRELESS2_QUERY 0x1b >>>> @@ -309,10 +310,18 @@ static int __init hp_wmi_bios_2009_later(void) >>>> static int hp_wmi_enable_hotkeys(void) >>>> { >>>> int ret; >>>> - int query = 0x6e; >>>> + int query = 0xff; >>>> + int value = 0x6e; >>>> >>>> - ret = hp_wmi_perform_query(HPWMI_BIOS_QUERY, 1, &query, sizeof(query), >>>> - 0); >>>> + ret = hp_wmi_perform_query(HPWMI_BIOS_QUERY, 0, &query, >>>> + 0, sizeof(query)); >>>> + >>>> + if (!query) { >>> >>> I suspect this should come after the test for ret. If there is a more >>> fundamental error, it would make sense to exit with -EINVAL first. Despite query >>> being initialized to 0xff, we have no guarantee the firmware won't set it to 0 >>> and still return an error. >> >> That makes sense. Another sticky bit is, do we want to fail on a device that >> doesn't need this? Not really. >> >> How about I throw out the initial read, because, the test for FEATURE2_QUERY >> is the bit that actually fixes the bug. The read is just fearful bug >> prevention. How is this? >> >> @@ -309,10 +310,13 @@ static int __init hp_wmi_bios_2009_later(void) >> static int hp_wmi_enable_hotkeys(void) >> { >> int ret; >> - int query = 0x6e; >> + int query; >> + int value = 0x6e; > > "Reverse Christmas Tree" ordering please (longest to shortest, and it's OK to > group like types: > > int value = 0x6e; > int query; > int ret; > > It's also fine to group like types, preferred by some maintainers, I'm not > particular, but do appreciate consistency. > > int value = 0x6e; > int query, ret; > > Both are acceptable. > > Is there a reason 0x6e doesn't merit some kind of a HP_WMI_QUERY_XYZ define? > Probably not. 0x6e is a magic value that goes into a magic EC register, 0xe6. There are a small handful of laptop models that need this value for hotkeys to work. I think these all came out in the 2008 time frame. Models after that period seem to have a different values, but as far as I know, the value is present at boot and the hotkeys just work. I've not heard of anyone else having a broken laptop and needing to write a different value. If one crops up then that is something that should be done, but it does not fit into the context of any existing enum. >> >> - ret = hp_wmi_perform_query(HPWMI_BIOS_QUERY, 1, &query, sizeof(query), >> - 0); >> + if (!hp_wmi_perform_query(HPWMI_FEATURE2_QUERY, 0, &query, >> + 0, sizeof(query))) >> + ret = hp_wmi_perform_query(HPWMI_BIOS_QUERY, 1, &value, >> + sizeof(value), 0); >> >> if (ret) >> return -EINVAL; > > The problem with this is it doesn't distinguish between the feature not being > present, and an actual failure, since it doesn't capture the ret of > FEATURE2_QUERY. > > Consider the possible return values for FEATURE2_QUERY on devices with the > feature and devices without, does the above code do the right thing in all > cases? > My line of thinking was that if the feature query fails for any reason then we probably don't want to perform the write. But I do understand building code for future use. How about I break that query out into it's own function like the 2009_later query. I'm not sure what it should be called because I'm not sure what it's actually for or when it actually appeared, but how about hp_wmi_bios_2008_later? > >> >> >>> >>> Rafael, would you agree? >>> >>> And technically, EINVAL isn't the right error for a general error (but that's a >>> preexisting problem). You don't have to fix that to get this in. >>> >>> >>>> + if (!hp_wmi_perform_query(HPWMI_FEATURE2_QUERY, 0, &query, >>>> + 0, sizeof(query))) >>>> + ret = hp_wmi_perform_query(HPWMI_BIOS_QUERY, 1, &value, >>> >>> Careful with indentation, use tabs please. checkpatch.pl would have caught this. >>> >>> >>>> + sizeof(value), 0); >>>> + } >>>> >>>> if (ret) >>>> return -EINVAL; >>>> @@ -663,7 +672,7 @@ static int __init hp_wmi_input_setup(void) >>>> hp_wmi_tablet_state()); >>>> input_sync(hp_wmi_input_dev); >>>> >>>> - if (hp_wmi_bios_2009_later() == 4) >>>> + if (hp_wmi_bios_2009_later() == HPWMI_RET_UNKNOWN_CMDTYPE) >>>> hp_wmi_enable_hotkeys(); >>> >>> This bit is fine, but no magic number cleanup is mentioned in the change log. >>> Was this change intentional? >> >> It was intentional but I didn't think it was worth a patch request. I had >> forgot that I made the change when creating a new patch and was on the fence >> about what to do about it so I didn't do anything. I'll be sure to call out >> that sort of thing in the future. > > Right, rolling it together with a semi-related change is OK for things like in > my opinion. But do make note of it in the changelog. >