From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Sakamoto Subject: Re: [PATCH 52/52] bebob: Add support for M-Audio special Firewire series Date: Wed, 26 Feb 2014 18:53:39 +0900 Message-ID: <530DB9A3.1020403@sakamocchi.jp> References: <1391003099-7109-1-git-send-email-o-takashi@sakamocchi.jp> <1391006977-11572-3-git-send-email-o-takashi@sakamocchi.jp> <530CA27D.2000306@sakamocchi.jp> <530CF745.40309@ladisch.de> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------080303000507080109000709" Return-path: In-Reply-To: <530CF745.40309@ladisch.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux1394-devel-bounces@lists.sourceforge.net To: Clemens Ladisch Cc: alsa-devel@alsa-project.org, linux1394-devel@lists.sourceforge.net, ffado-devel@lists.sf.net List-Id: alsa-devel@alsa-project.org This is a multi-part message in MIME format. --------------080303000507080109000709 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Clemens, Thanks for your quick reply. > Maybe we should change how these functions handle timeouts. Any other > error code indicates that the lock transaction failed definitely, but > after a timeout, we don't know if it was the request or the response > that got lost. > > We could try to read the register, and, if we see that the change that we > tried to do actually happend, assume that our driver's transaction did > this change. How is attached patch for this idea? > Are read transactions more reliable than locks? If not, we might need > to increase the number of retries for these devices. This quirk is applied for all of transactions to these devices. As long as I expeciment, their reliability roughly the same. As long as I tested with this patch, the current number of retries (3 times) seemd to be enough for these devices. ALSA applications can safely use PCM character devices. > This patch (no. 52) does not change the CMP code. I had no plan to touch CMP codes for this patch because just two models have this quirk. But now I want to add this patch into my series of patch. Thanks Takashi Sakamoto o-takashi@sakamocchi.jp --------------080303000507080109000709 Content-Type: text/x-patch; name="0001-firewire-lib-add-a-fallback-at-RCODE_CANCELLED.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename*0="0001-firewire-lib-add-a-fallback-at-RCODE_CANCELLED.patch" >>From e2a4091de645dddc116fe194b71ab20117a4f377 Mon Sep 17 00:00:00 2001 From: Takashi Sakamoto Date: Wed, 26 Feb 2014 13:42:32 +0900 Subject: [PATCH] firewire-lib: add a fallback at RCODE_CANCELLED I confirm that some devices often send no response against driver's request even if the devices handle the request. In this case, drivers should not retry the request because the devices already handled an operation of the request. The second request may bring errors or make no sence. This patch adds a flag, FW_RETURN_TIMEOUT, for snd_fw_transaction(). With this flag, this function returns -ETIMEOUT when fw_run_transaction() returns RCODE_CALCELLED., For FCP, this patch modifies fcp_avc_transaction() with this flag. The -ETIMEDOUT is handled as success. For CMP, this patch modifies pcr_modify() with this flag. The -ETIMEOUT generates another read transaction to check current value of PCR. --- sound/firewire/cmp.c | 23 +++++++++++++++++++++-- sound/firewire/fcp.c | 5 +++-- sound/firewire/lib.c | 6 +++++- sound/firewire/lib.h | 1 + 4 files changed, 30 insertions(+), 5 deletions(-) diff --git a/sound/firewire/cmp.c b/sound/firewire/cmp.c index efdbf58..1fc332a 100644 --- a/sound/firewire/cmp.c +++ b/sound/firewire/cmp.c @@ -60,13 +60,32 @@ static int pcr_modify(struct cmp_connection *c, c->resources.unit, TCODE_LOCK_COMPARE_SWAP, CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index), buffer, 8, - FW_FIXED_GENERATION | c->resources.generation); + FW_FIXED_GENERATION | c->resources.generation | + FW_RETURN_TIMEOUT); if (err < 0) { if (err == -EAGAIN && bus_reset_handling == SUCCEED_ON_BUS_RESET) err = 0; - return err; + + if (err != -ETIMEDOUT) + return err; + + /* Check current PCR. */ + err = snd_fw_transaction( + c->resources.unit, TCODE_READ_QUADLET_REQUEST, + CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index), + buffer, 4, + FW_FIXED_GENERATION | c->resources.generation); + if (err < 0) + return err; + + /* The lock transaction may be failed, retry */ + if (buffer[0] != buffer[1]) { + buffer[0] = c->last_pcr_value; + continue; + } + break; } if (buffer[0] == old_arg) /* success? */ diff --git a/sound/firewire/fcp.c b/sound/firewire/fcp.c index 860c080..5bb1cdf 100644 --- a/sound/firewire/fcp.c +++ b/sound/firewire/fcp.c @@ -90,8 +90,9 @@ int fcp_avc_transaction(struct fw_unit *unit, : TCODE_WRITE_BLOCK_REQUEST; ret = snd_fw_transaction(t.unit, tcode, CSR_REGISTER_BASE + CSR_FCP_COMMAND, - (void *)command, command_size, 0); - if (ret < 0) + (void *)command, command_size, + FW_RETURN_TIMEOUT); + if ((ret < 0) && (ret != -ETIMEDOUT)) break; wait_event_timeout(t.wait, t.state != STATE_PENDING, diff --git a/sound/firewire/lib.c b/sound/firewire/lib.c index 7409edb..6c3278b 100644 --- a/sound/firewire/lib.c +++ b/sound/firewire/lib.c @@ -22,7 +22,7 @@ * @length: length of @buffer * @flags: use %FW_FIXED_GENERATION and add the generation value to attempt the * request only in that generation; use %FW_QUIET to suppress error - * messages + * messages: use %FW_RETURN_TIMEOUT to avoid retry at RCODE_CANCELLED * * Submits an asynchronous request to the target device, and waits for the * response. The node ID and the current generation are derived from @unit. @@ -53,6 +53,10 @@ int snd_fw_transaction(struct fw_unit *unit, int tcode, if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION)) return -EAGAIN; + /* timeout */ + if ((rcode == RCODE_CANCELLED) && (flags & FW_RETURN_TIMEOUT)) + return -ETIMEDOUT; + if (rcode_is_permanent_error(rcode) || ++tries >= 3) { if (!(flags & FW_QUIET)) dev_err(&unit->device, diff --git a/sound/firewire/lib.h b/sound/firewire/lib.h index 02cfabc..b8ea90b 100644 --- a/sound/firewire/lib.h +++ b/sound/firewire/lib.h @@ -9,6 +9,7 @@ struct fw_unit; #define FW_GENERATION_MASK 0x00ff #define FW_FIXED_GENERATION 0x0100 #define FW_QUIET 0x0200 +#define FW_RETURN_TIMEOUT 0x0400 int snd_fw_transaction(struct fw_unit *unit, int tcode, u64 offset, void *buffer, size_t length, -- 1.8.3.2 --------------080303000507080109000709 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline ------------------------------------------------------------------------------ Flow-based real-time traffic analytics software. 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