From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay7-d.mail.gandi.net (relay7-d.mail.gandi.net [217.70.183.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BDB66128819; Fri, 23 May 2025 14:39:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748011180; cv=none; b=lhKgFoucKN5DTATTt6b30Bor+PWx4+4p3/CPa3V+x9QunZiqkY9Oi9PJwDc7/EFD60AGQmBlRDe1NQ7+tVkknOsG23hf8X96WzOqr4ymTxocZS22MeJUd7fddV0DZnydPY2PhDDtqbyY+vXiy8W7rTindrk45AZhrx716LTGCR8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748011180; c=relaxed/simple; bh=ZOCK6JsdZd/ExEyqrEPPTB1IZhrxIX3Mph1RiKKr0VI=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=g8DBV9N+674cuk9Kw2Jn70cAmge3zXu6Vcvc9DyuGiwpPmCAy+Omll0ZfeOB3ugD+8C+o0zYOCzTbWlfaYmAqqPYO/oQdeEaXcswJhWS9xVHPj+JgkgAPUUuLT5RGFFI7YXCAa3VgrnPy+Cie6WVcloEP0EXWqJFS873R4az/ds= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=OBVIR7YF; arc=none smtp.client-ip=217.70.183.200 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="OBVIR7YF" Received: by mail.gandi.net (Postfix) with ESMTPSA id 9CD534397D; Fri, 23 May 2025 14:39:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1748011176; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZOCK6JsdZd/ExEyqrEPPTB1IZhrxIX3Mph1RiKKr0VI=; b=OBVIR7YFZYAUkFrhZKMUINmFTYrEstapjIs7fISyxAuP6w6BZeuHjCzzh2WzYmq/RDOvK0 qSo+jIEmhlJo1ptMCBgSzlIeCevKk2ejF4fpyJPQK2fQrqPE3inng3jBTQHjihbaTAHUR7 Wfku5P8ArQRpTqmoskd15GoP1wkQrBXqscUxBh1FSH7P4YTTCsH8op/L5rub8Q4lEpOOPe IxNNjYjmwAjiyQ6BBOU7RNONEQmj4doZdwbkYyiKqAh0wqVAvKt5a4NcyqNHcrjHrJq2VX 2/fFDa9SjE8340EeZ62B2SIs0qXboBRweqI/NMb5GWwhysh0y9gJzvM9D7KVkg== From: Miquel Raynal To: Gabor Juhos Cc: Mark Brown , Md Sadre Alam , Varadarajan Narayanan , Sricharan Ramabadhran , linux-spi@vger.kernel.org, linux-mtd@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC] spi: spi-qpic-snand: overestimate corrected bitflips In-Reply-To: <20250522-qpic-snand-overestimate-bitflips-v1-1-35c65c05068e@gmail.com> (Gabor Juhos's message of "Thu, 22 May 2025 19:33:26 +0200") References: <20250522-qpic-snand-overestimate-bitflips-v1-1-35c65c05068e@gmail.com> User-Agent: mu4e 1.12.7; emacs 29.4 Date: Fri, 23 May 2025 16:39:33 +0200 Message-ID: <875xhr5r2y.fsf@bootlin.com> Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtddtgdeluddvucdltddurdegfedvrddttddmucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuifetpfffkfdpucggtfgfnhhsuhgsshgtrhhisggvnecuuegrihhlohhuthemuceftddunecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpefhvfevufgjfhgffffkgggtgfesthhqredttderjeenucfhrhhomhepofhiqhhuvghlucftrgihnhgrlhcuoehmihhquhgvlhdrrhgrhihnrghlsegsohhothhlihhnrdgtohhmqeenucggtffrrghtthgvrhhnpeejgeeftdefledvieegvdejlefgleegjefhgfeuleevgfdtjeehudffhedvheegueenucffohhmrghinhepkhgvrhhnvghlrdhorhhgnecukfhppeelvddrudekgedrleekrddtnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepledvrddukeegrdelkedrtddphhgvlhhopehlohgtrghlhhhoshhtpdhmrghilhhfrhhomhepmhhiqhhuvghlrdhrrgihnhgrlhessghoohhtlhhinhdrtghomhdpnhgspghrtghpthhtohepledprhgtphhtthhopehjgehgkeihjeesghhmrghilhdrtghomhdprhgtphhtthhopegsrhhoohhnihgvsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehquhhitggpmhgurghlrghmsehquhhitghinhgtrdgtohhmpdhrtghpthhtohepqhhuihgtpghvrghrrggurgesqhhuihgtihhntgdrtghomhdprhgtphhtthhopehquhhitggps hhrihgthhgrrhgrsehquhhitghinhgtrdgtohhmpdhrtghpthhtoheplhhinhhugidqshhpihesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehlihhnuhigqdhmthgusehlihhsthhsrdhinhhfrhgruggvrggurdhorhhgpdhrtghpthhtoheplhhinhhugidqrghrmhdqmhhsmhesvhhgvghrrdhkvghrnhgvlhdrohhrgh X-GND-Sasl: miquel.raynal@bootlin.com On 22/05/2025 at 19:33:26 +02, Gabor Juhos wrote: > The QPIC hardware is not capable of reporting the exact number of the > corrected bitflips, it only reports the number of the corrected bytes. > However the current code treats that as corrected bitflips which is > quite inaccurate in most cases. For example, even if the hardware reports > only one byte as corrected, that byte may have contained multiple bit > errors from one up to the maximum number of correctable bits. > > Change the code to report the maximum of the possibly corrected bits, > thus allowing upper layers to do certain actions before the data gets > lost due to uncorrectable errors. > > Signed-off-by: Gabor Juhos > --- > The patch tries to address Miquel's concerns [1] about the corrected bit > error reporting capabilities of the QPIC hardware. > > [1] https://lore.kernel.org/all/87h61e8kow.fsf@bootlin.com Thank you very much for attempting to improve the situation. Giving this a second look, it will not work either and will be even worse, forcing wear levelling after each read. So let's not change the returned value, hopefully the real life is different as the test case and most bitflips will be spread and not concentrated in a single byte. However I'd welcome either a pr_warn_once() or at least a comment somewhere about this. Thanks, Miqu=C3=A8l From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F1D07C54ED0 for ; Fri, 23 May 2025 15:09:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:References :In-Reply-To:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=oH3/BrbXJVSCTzcZiYOtyqNrdtteG78u2uTwaFQribw=; b=McbcqDAkTf7hY4 dEBc/RKyT4LTH/RIU8xinKY0pMnkZKam86WwaZbygXHY7qyQNR8tpHi80Sdc0+rRnBUOr5UkXaJmZ Mvfpya0X7pKn4UYXnPoWT5pVoAUmVFtVjeClSczcRcHqCyccY6/RDEu6KAAcSUCO/db8a/yC2z0SN JLA/FpTKyLROwWB9dcps2ekhCOZmuj2bGCZwtB33NBsbzxvw6Kzcl8t/8BszJ7V4DuDmPTU/oVDSr swQQjQV2CsQUPdif0l5GKORk+MeZZhN7+GrHXSfdTd8Oefdb2lqkrOZpHKt9frPngOwpffdKFWTJ0 tbce5YHj4YrzNeOAqzvQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uIU1o-00000004CEo-44bW; Fri, 23 May 2025 15:09:44 +0000 Received: from relay7-d.mail.gandi.net ([2001:4b98:dc4:8::227]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uITYq-000000045PJ-2oJO for linux-mtd@lists.infradead.org; Fri, 23 May 2025 14:39:50 +0000 Received: by mail.gandi.net (Postfix) with ESMTPSA id 9CD534397D; Fri, 23 May 2025 14:39:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1748011176; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZOCK6JsdZd/ExEyqrEPPTB1IZhrxIX3Mph1RiKKr0VI=; b=OBVIR7YFZYAUkFrhZKMUINmFTYrEstapjIs7fISyxAuP6w6BZeuHjCzzh2WzYmq/RDOvK0 qSo+jIEmhlJo1ptMCBgSzlIeCevKk2ejF4fpyJPQK2fQrqPE3inng3jBTQHjihbaTAHUR7 Wfku5P8ArQRpTqmoskd15GoP1wkQrBXqscUxBh1FSH7P4YTTCsH8op/L5rub8Q4lEpOOPe IxNNjYjmwAjiyQ6BBOU7RNONEQmj4doZdwbkYyiKqAh0wqVAvKt5a4NcyqNHcrjHrJq2VX 2/fFDa9SjE8340EeZ62B2SIs0qXboBRweqI/NMb5GWwhysh0y9gJzvM9D7KVkg== From: Miquel Raynal To: Gabor Juhos Cc: Mark Brown , Md Sadre Alam , Varadarajan Narayanan , Sricharan Ramabadhran , linux-spi@vger.kernel.org, linux-mtd@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC] spi: spi-qpic-snand: overestimate corrected bitflips In-Reply-To: <20250522-qpic-snand-overestimate-bitflips-v1-1-35c65c05068e@gmail.com> (Gabor Juhos's message of "Thu, 22 May 2025 19:33:26 +0200") References: <20250522-qpic-snand-overestimate-bitflips-v1-1-35c65c05068e@gmail.com> User-Agent: mu4e 1.12.7; emacs 29.4 Date: Fri, 23 May 2025 16:39:33 +0200 Message-ID: <875xhr5r2y.fsf@bootlin.com> MIME-Version: 1.0 X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtddtgdeluddvucdltddurdegfedvrddttddmucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuifetpfffkfdpucggtfgfnhhsuhgsshgtrhhisggvnecuuegrihhlohhuthemuceftddunecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpefhvfevufgjfhgffffkgggtgfesthhqredttderjeenucfhrhhomhepofhiqhhuvghlucftrgihnhgrlhcuoehmihhquhgvlhdrrhgrhihnrghlsegsohhothhlihhnrdgtohhmqeenucggtffrrghtthgvrhhnpeejgeeftdefledvieegvdejlefgleegjefhgfeuleevgfdtjeehudffhedvheegueenucffohhmrghinhepkhgvrhhnvghlrdhorhhgnecukfhppeelvddrudekgedrleekrddtnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepledvrddukeegrdelkedrtddphhgvlhhopehlohgtrghlhhhoshhtpdhmrghilhhfrhhomhepmhhiqhhuvghlrdhrrgihnhgrlhessghoohhtlhhinhdrtghomhdpnhgspghrtghpthhtohepledprhgtphhtthhopehjgehgkeihjeesghhmrghilhdrtghomhdprhgtphhtthhopegsrhhoohhnihgvsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehquhhitggpmhgurghlrghmsehquhhitghinhgtrdgtohhmpdhrtghpthhtohepqhhuihgtpghvrghrrggurgesqhhuihgtihhntgdrtghomhdprhgtphhtthhopehquhhitggps hhrihgthhgrrhgrsehquhhitghinhgtrdgtohhmpdhrtghpthhtoheplhhinhhugidqshhpihesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehlihhnuhigqdhmthgusehlihhsthhsrdhinhhfrhgruggvrggurdhorhhgpdhrtghpthhtoheplhhinhhugidqrghrmhdqmhhsmhesvhhgvghrrdhkvghrnhgvlhdrohhrgh X-GND-Sasl: miquel.raynal@bootlin.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250523_073948_857976_31116C72 X-CRM114-Status: GOOD ( 12.78 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org T24gMjIvMDUvMjAyNSBhdCAxOTozMzoyNiArMDIsIEdhYm9yIEp1aG9zIDxqNGc4eTdAZ21haWwu Y29tPiB3cm90ZToKCj4gVGhlIFFQSUMgaGFyZHdhcmUgaXMgbm90IGNhcGFibGUgb2YgcmVwb3J0 aW5nIHRoZSBleGFjdCBudW1iZXIgb2YgdGhlCj4gY29ycmVjdGVkIGJpdGZsaXBzLCBpdCBvbmx5 IHJlcG9ydHMgdGhlIG51bWJlciBvZiB0aGUgY29ycmVjdGVkIGJ5dGVzLgo+IEhvd2V2ZXIgdGhl IGN1cnJlbnQgY29kZSB0cmVhdHMgdGhhdCBhcyBjb3JyZWN0ZWQgYml0ZmxpcHMgd2hpY2ggaXMK PiBxdWl0ZSBpbmFjY3VyYXRlIGluIG1vc3QgY2FzZXMuIEZvciBleGFtcGxlLCBldmVuIGlmIHRo ZSBoYXJkd2FyZSByZXBvcnRzCj4gb25seSBvbmUgYnl0ZSBhcyBjb3JyZWN0ZWQsIHRoYXQgYnl0 ZSBtYXkgaGF2ZSBjb250YWluZWQgbXVsdGlwbGUgYml0Cj4gZXJyb3JzIGZyb20gb25lIHVwIHRv IHRoZSBtYXhpbXVtIG51bWJlciBvZiBjb3JyZWN0YWJsZSBiaXRzLgo+Cj4gQ2hhbmdlIHRoZSBj b2RlIHRvIHJlcG9ydCB0aGUgbWF4aW11bSBvZiB0aGUgcG9zc2libHkgY29ycmVjdGVkIGJpdHMs Cj4gdGh1cyBhbGxvd2luZyB1cHBlciBsYXllcnMgdG8gZG8gY2VydGFpbiBhY3Rpb25zIGJlZm9y ZSB0aGUgZGF0YSBnZXRzCj4gbG9zdCBkdWUgdG8gdW5jb3JyZWN0YWJsZSBlcnJvcnMuCj4KPiBT aWduZWQtb2ZmLWJ5OiBHYWJvciBKdWhvcyA8ajRnOHk3QGdtYWlsLmNvbT4KPiAtLS0KPiBUaGUg cGF0Y2ggdHJpZXMgdG8gYWRkcmVzcyBNaXF1ZWwncyBjb25jZXJucyBbMV0gYWJvdXQgdGhlIGNv cnJlY3RlZCBiaXQKPiBlcnJvciByZXBvcnRpbmcgY2FwYWJpbGl0aWVzIG9mIHRoZSBRUElDIGhh cmR3YXJlLgo+Cj4gWzFdIGh0dHBzOi8vbG9yZS5rZXJuZWwub3JnL2FsbC84N2g2MWU4a293LmZz ZkBib290bGluLmNvbQoKVGhhbmsgeW91IHZlcnkgbXVjaCBmb3IgYXR0ZW1wdGluZyB0byBpbXBy b3ZlIHRoZSBzaXR1YXRpb24uIEdpdmluZyB0aGlzCmEgc2Vjb25kIGxvb2ssIGl0IHdpbGwgbm90 IHdvcmsgZWl0aGVyIGFuZCB3aWxsIGJlIGV2ZW4gd29yc2UsIGZvcmNpbmcKd2VhciBsZXZlbGxp bmcgYWZ0ZXIgZWFjaCByZWFkLiBTbyBsZXQncyBub3QgY2hhbmdlIHRoZSByZXR1cm5lZCB2YWx1 ZSwKaG9wZWZ1bGx5IHRoZSByZWFsIGxpZmUgaXMgZGlmZmVyZW50IGFzIHRoZSB0ZXN0IGNhc2Ug YW5kIG1vc3QgYml0ZmxpcHMKd2lsbCBiZSBzcHJlYWQgYW5kIG5vdCBjb25jZW50cmF0ZWQgaW4g YSBzaW5nbGUgYnl0ZS4gSG93ZXZlciBJJ2QKd2VsY29tZSBlaXRoZXIgYSBwcl93YXJuX29uY2Uo KSBvciBhdCBsZWFzdCBhIGNvbW1lbnQgc29tZXdoZXJlIGFib3V0CnRoaXMuCgpUaGFua3MsCk1p cXXDqGwKCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fXwpMaW51eCBNVEQgZGlzY3Vzc2lvbiBtYWlsaW5nIGxpc3QKaHR0cDovL2xpc3RzLmluZnJh ZGVhZC5vcmcvbWFpbG1hbi9saXN0aW5mby9saW51eC1tdGQvCg==