From patchwork Thu Dec 7 13:26:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Neukum X-Patchwork-Id: 752465 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="CVZE7JSk" Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2a07:de40:b251:101:10:150:64:2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0675CAA for ; Thu, 7 Dec 2023 05:26:43 -0800 (PST) Received: from imap2.dmz-prg2.suse.org (imap2.dmz-prg2.suse.org [10.150.64.98]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 8801B1FB5B; Thu, 7 Dec 2023 13:26:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1701955602; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=PRjokn8ymlmJiE3WTalVFwVkyc7m7Nrc4bVoc9q+N1E=; b=CVZE7JSkNCoZOwYOzqJaSmd874jo1eWTHVB4l9PkwvhLibNiINVgdN36HrLIA8tzhAf+UY rNFKgtgtWpBYc42nkO3CHHcVSF85fMULyGoiQVHA9UfxezNBlzkgKXgal3pHU4vo36k4cb jMYnBmLknNClDZbgCCC5GaLBIZ+ovOg= Received: from imap2.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap2.dmz-prg2.suse.org (Postfix) with ESMTPS id 3A65213907; Thu, 7 Dec 2023 13:26:42 +0000 (UTC) Received: from dovecot-director2.suse.de ([10.150.64.162]) by imap2.dmz-prg2.suse.org with ESMTPSA id vbyGCxLIcWVtEgAAn2gu4w (envelope-from ); Thu, 07 Dec 2023 13:26:42 +0000 From: Oliver Neukum To: gregkh@linuxfoundation.org, hovold@kernel.org, linux-usb@vger.kernel.org Cc: Oliver Neukum Subject: [PATCH] usb: cdc-acm: return correct error code on unsupported break Date: Thu, 7 Dec 2023 14:26:30 +0100 Message-ID: <20231207132639.18250-1-oneukum@suse.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spamd-Result: default: False [4.98 / 50.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; BAYES_SPAM(0.08)[59.18%]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[4]; R_MISSING_CHARSET(2.50)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; BROKEN_CONTENT_TYPE(1.50)[]; TO_DN_SOME(0.00)[]; RCVD_COUNT_THREE(0.00)[3]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; MID_CONTAINS_FROM(1.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:email]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_ALL(0.00)[] Authentication-Results: smtp-out2.suse.de; none X-Spam-Score: 4.98 In ACM support for sending breaks to devices is optional. If a device says that it doenot support sending breaks, the host must respect that. Given the number of optional features providing tty operations for each combination is not practical and errors need to be returned dynamically if unsupported features are requested. In case a device does not support break, we want the tty layer to treat that like it treats drivers that statically cannot support sending a break. It ignores the inability and does nothing. This patch uses EOPNOTSUPP to indicate that. Signed-off-by: Oliver Neukum Fixes: 9e98966c7bb94 ("tty: rework break handling") --- drivers/tty/tty_io.c | 3 +++ drivers/usb/class/cdc-acm.c | 3 +++ 2 files changed, 6 insertions(+) diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 06414e43e0b5..96617f9af819 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -2489,6 +2489,9 @@ static int send_break(struct tty_struct *tty, unsigned int duration) if (!retval) { msleep_interruptible(duration); retval = tty->ops->break_ctl(tty, 0); + } else if (retval == -EOPNOTSUPP) { + /* some drivers can tell only dynamically */ + retval = 0; } tty_write_unlock(tty); diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index a1f4e1ead97f..0e7439dba8fe 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -916,6 +916,9 @@ static int acm_tty_break_ctl(struct tty_struct *tty, int state) struct acm *acm = tty->driver_data; int retval; + if (!(acm->ctrl_caps & USB_CDC_CAP_BRK)) + return -EOPNOTSUPP; + retval = acm_send_break(acm, state ? 0xffff : 0); if (retval < 0) dev_dbg(&acm->control->dev,