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Wysocki" Cc: "Rafael J. Wysocki" , Linux ACPI , LKML , Andy Shevchenko , Hans de Goede , Mario Limonciello , Heikki Krogerus References: <5787281.DvuYhMxLoT@kreacher> <4926735.31r3eYUQgx@kreacher> Content-Language: en-US From: Armin Wolf In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:65zII5bXn7iGnNlKowCzVpQpphVdt6/gLiy+9vE9bdqUagLeE1+ 8DYZyTLyqHq+vPT6WDRAwUdkfBRjzNzBuFl/y5BJgEC/asgrKEx1Zqp0VDYaosVcjneCsb3 AYnkGLG6PzXyrU3mbUdN8dbeOE5iuVaMx+jJ7SAokboSK6CADSsFNPPjHmLu7jE0GG6YWbS BKtIY333VN27THAkvZbEA== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:MxWBLCHTiOE=;zivxnuFUWIO8ZckWjLUWROWykZ7 IviydntdKeRc4kvo42JvpZniPyQ3yS1z09840MYgFJLdbIP1Mg6AVJxPCw7aqd9yhU+WOtdD5 /mhk2FSOTEhJTRyRc+U3BoUbKhcZ1IAqtcW/8GzDLOtVgfM5ieRcFFfP1phuT6G5Cb0X9NyVp iYiFFlTdhO+ZubE4uVRnFLTkOZ+VfcmFOJBl1hjoG3mDO1/ZOzcD10eNuvrYzmTIePKqczDkI wj5AnqXkdGSFqisiGUvdVphQBAkmCAeU/s8kfc1LRDOEIh+dTE//S7gvTkO4dkPGyEW0SSqJN 5BZUBlZobNkWKK9fcH1XC5cCrfu6U7BtrSad7TYKf5sE0dS8KCdJPE5jMxUN+BjJz24xwsww2 6u0fUBoDXhuh0XxSJxmokVgASvGKwPm06yECSKkvvGcoDcKQ23ygKoKrPSPh7K/13ijtP9mJb k7KgkuASAH9hvG7H4b4t/SM8Rikip6Sqe5NJHuypG/UL07aTJFbEkcLqCv3jxFexc/knej5Gx Z1C7LkheHRnalqP0JLXC/5jKgFcr3SVCMx59I26vKy8pCME/h+88IgGRyYLnKWRi1f8BAvuYL YnqVkswQOKtT+V4EZlaNA85DcijA5uU0njnpXOMr/lQbuwhPjBxJsBUGxDkatSZNrYxJszkL6 9aODojqTgiw3j5UFnub+M/hyEMEkSS8yikQx9y8ivwJ++oeBMqr2hSfmWk51TVq4dZT5A5msl HjmM/ZYI8Vr8hfgSVhxPtc/C8ZTSvwPy3B+bjS1PFOz1C+HHSWfs0egr9h8AU+G3gpdq1JrvD MuBjemZsfc5oAjYpKpWqHHXLVVysmNLrZdh4XdSizzORM= Am 10.05.24 um 18:41 schrieb Rafael J. Wysocki: > On Fri, May 10, 2024 at 6:10=E2=80=AFPM Armin Wolf wrot= e: >> Am 10.05.24 um 16:03 schrieb Rafael J. Wysocki: >> >>> From: Rafael J. Wysocki >>> >>> It is reported that _DSM evaluation fails in ucsi_acpi_dsm() on Lenovo >>> IdeaPad Pro 5 due to a missing address space handler for the EC addres= s >>> space: >>> >>> ACPI Error: No handler for Region [ECSI] (000000007b8176ee) [Embedd= edControl] (20230628/evregion-130) >>> >>> This happens because the EC driver only registers the EC address space >>> handler for operation regions defined in the EC device scope of the >>> ACPI namespace while the operation region being accessed by the _DSM >>> in question is located beyond that scope. >>> >>> To address this, modify the ACPI EC driver to install the EC address >>> space handler at the root of the ACPI namespace. >>> >>> Note that this change is consistent with some examples in the ACPI >>> specification in which EC operation regions located outside the EC >>> device scope are used (for example, see Section 9.17.15 in ACPI 6.5), >>> so the current behavior of the EC driver is arguably questionable. >> Hi, >> >> the patch itself looks good to me, but i wonder what happens if multipl= e >> ACPI EC devices are present. How would we handle such a situation? > I'm wondering if this is a theoretical question or do you have any > existing or planned systems in mind? > > ec_read(), ec_write() and ec_transaction() use only the first EC that > has been found anyway. Its a theoretical question, i do not know of any systems which have more t= han one ACPI EC device. This patch would prevent any ACPI ECs other than the first one from probin= g, since they would fail to register their address space handler. I am just curious if/how we want to handle such situations. Thanks, Armin Wolf